From 69721b930ae3dbdb992fa966918c3c2990003ca1 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Sun, 26 Jul 2015 04:48:42 +0100
Subject: [PATCH] add token match method and remove more dead code

---
 packages/babylon/src/parser/comments.js   |   6 +-
 packages/babylon/src/parser/expression.js | 252 +++++++++++-----------
 packages/babylon/src/parser/lval.js       |   8 +-
 packages/babylon/src/parser/statement.js  |  90 ++++----
 packages/babylon/src/parser/util.js       |  35 +--
 packages/babylon/src/plugins/flow.js      |  76 +++----
 packages/babylon/src/plugins/jsx/index.js |  16 +-
 packages/babylon/src/tokenizer/index.js   |  23 +-
 packages/babylon/src/tokenizer/state.js   |   2 +-
 9 files changed, 251 insertions(+), 257 deletions(-)

diff --git a/packages/babylon/src/parser/comments.js b/packages/babylon/src/parser/comments.js
index 53a4fc3f73..65de15b5c6 100644
--- a/packages/babylon/src/parser/comments.js
+++ b/packages/babylon/src/parser/comments.js
@@ -38,7 +38,7 @@ pp.addComment = function (comment) {
 pp.processComment = function (node) {
   if (node.type === "Program" && node.body.length > 0) return;
 
-  var stack = this.state.bottomRightStack;
+  var stack = this.state.commentStack;
 
   var lastChild, trailingComments, i;
 
@@ -80,7 +80,7 @@ pp.processComment = function (node) {
       } else {
         // A leading comment for an anonymous class had been stolen by its first MethodDefinition,
         // so this takes back the leading comment.
-        // See Also: https://github.com/eslint/espree/issues/158
+        // See also: https://github.com/eslint/espree/issues/158
         for (i = lastChild.leadingComments.length - 2; i >= 0; --i) {
           if (lastChild.leadingComments[i].end <= node.start) {
             node.leadingComments = lastChild.leadingComments.splice(0, i + 1);
@@ -99,7 +99,7 @@ pp.processComment = function (node) {
       // In special cases, such as return (without a value) and
       // debugger, all comments will end up as leadingComments and
       // will otherwise be eliminated. This this step runs when the
-      // bottomRightStack is empty and there are comments left
+      // commentStack is empty and there are comments left
       // in leadingComments.
       //
       // This loop figures out the stopping point between the actual
diff --git a/packages/babylon/src/parser/expression.js b/packages/babylon/src/parser/expression.js
index 38f52cde4a..56d7e0b342 100644
--- a/packages/babylon/src/parser/expression.js
+++ b/packages/babylon/src/parser/expression.js
@@ -62,7 +62,7 @@ pp.checkPropClash = function (prop, propHash) {
 pp.parseExpression = function (noIn, refShorthandDefaultPos) {
   let startPos = this.state.start, startLoc = this.state.startLoc;
   let expr = this.parseMaybeAssign(noIn, refShorthandDefaultPos);
-  if (this.state.type === tt.comma) {
+  if (this.match(tt.comma)) {
     let node = this.startNodeAt(startPos, startLoc);
     node.expressions = [expr];
     while (this.eat(tt.comma)) {
@@ -78,7 +78,7 @@ pp.parseExpression = function (noIn, refShorthandDefaultPos) {
 // operators like `+=`.
 
 pp.parseMaybeAssign = function (noIn, refShorthandDefaultPos, afterLeftParse) {
-  if (this.state.type === tt._yield && this.state.inGenerator) {
+  if (this.match(tt._yield) && this.state.inGenerator) {
     return this.parseYield();
   }
 
@@ -90,7 +90,7 @@ pp.parseMaybeAssign = function (noIn, refShorthandDefaultPos, afterLeftParse) {
     failOnShorthandAssign = false;
   }
   let startPos = this.state.start, startLoc = this.state.startLoc;
-  if (this.state.type === tt.parenL || this.state.type === tt.name) {
+  if (this.match(tt.parenL) || this.match(tt.name)) {
     this.state.potentialArrowAt = this.state.start;
   }
   let left = this.parseMaybeConditional(noIn, refShorthandDefaultPos);
@@ -98,7 +98,7 @@ pp.parseMaybeAssign = function (noIn, refShorthandDefaultPos, afterLeftParse) {
   if (this.state.type.isAssign) {
     let node = this.startNodeAt(startPos, startLoc);
     node.operator = this.state.value;
-    node.left = this.state.type === tt.eq ? this.toAssignable(left) : left;
+    node.left = this.match(tt.eq) ? this.toAssignable(left) : left;
     refShorthandDefaultPos.start = 0; // reset because shorthand default was used correctly
     this.checkLVal(left);
     if (left.parenthesizedExpression) {
@@ -155,7 +155,7 @@ pp.parseExprOps = function (noIn, refShorthandDefaultPos) {
 
 pp.parseExprOp = function(left, leftStartPos, leftStartLoc, minPrec, noIn) {
   let prec = this.state.type.binop;
-  if (prec != null && (!noIn || this.state.type !== tt._in)) {
+  if (prec != null && (!noIn || !this.match(tt._in))) {
     if (prec > minPrec) {
       let node = this.startNodeAt(leftStartPos, leftStartLoc);
       node.left = left;
@@ -175,7 +175,7 @@ pp.parseExprOp = function(left, leftStartPos, leftStartLoc, minPrec, noIn) {
 
 pp.parseMaybeUnary = function (refShorthandDefaultPos) {
   if (this.state.type.prefix) {
-    let node = this.startNode(), update = this.state.type === tt.incDec;
+    let node = this.startNode(), update = this.match(tt.incDec);
     node.operator = this.state.value;
     node.prefix = true;
     this.next();
@@ -235,7 +235,7 @@ pp.parseSubscripts = function(base, startPos, startLoc, noCalls) {
       node.computed = true;
       this.expect(tt.bracketR);
       base = this.finishNode(node, "MemberExpression");
-    } else if (!noCalls && this.state.type === tt.parenL) {
+    } else if (!noCalls && this.match(tt.parenL)) {
       let possibleAsync = base.type === "Identifier" && base.name === "async" && !this.canInsertSemicolon();
       this.next();
 
@@ -244,12 +244,12 @@ pp.parseSubscripts = function(base, startPos, startLoc, noCalls) {
       node.arguments = this.parseExprList(tt.parenR, this.options.features["es7.trailingFunctionCommas"]);
       base = this.finishNode(node, "CallExpression");
 
-      if (possibleAsync && (this.state.type === tt.colon || this.state.type === tt.arrow)) {
+      if (possibleAsync && (this.match(tt.colon) || this.match(tt.arrow))) {
         base = this.parseAsyncArrowFromCallExpression(this.startNodeAt(startPos, startLoc), node);
       } else {
         this.toReferencedList(node.arguments);
       }
-    } else if (this.state.type === tt.backQuote) {
+    } else if (this.match(tt.backQuote)) {
       let node = this.startNodeAt(startPos, startLoc);
       node.tag = base;
       node.quasi = this.parseTemplate();
@@ -281,122 +281,122 @@ pp.parseNoCallExpr = function () {
 pp.parseExprAtom = function (refShorthandDefaultPos) {
   let node, canBeArrow = this.state.potentialArrowAt === this.state.start;
   switch (this.state.type) {
-  case tt._super:
-    if (!this.state.inFunction)
-      this.raise(this.state.start, "'super' outside of function or class");
-  case tt._this:
-    let type = this.state.type === tt._this ? "ThisExpression" : "Super";
-    node = this.startNode();
-    this.next();
-    return this.finishNode(node, type);
-
-  case tt._yield:
-    if (this.state.inGenerator) this.unexpected();
-
-  case tt._do:
-    if (this.options.features["es7.doExpressions"]) {
-      let node = this.startNode();
+    case tt._super:
+      if (!this.state.inFunction)
+        this.raise(this.state.start, "'super' outside of function or class");
+    case tt._this:
+      let type = this.match(tt._this) ? "ThisExpression" : "Super";
+      node = this.startNode();
       this.next();
-      var oldInFunction = this.state.inFunction;
-      var oldLabels = this.state.labels;
-      this.state.labels = [];
-      this.state.inFunction = false;
-      node.body = this.parseBlock();
-      this.state.inFunction = oldInFunction;
-      this.state.labels = oldLabels;
-      return this.finishNode(node, "DoExpression");
-    }
+      return this.finishNode(node, type);
 
-  case tt.name:
-    node = this.startNode();
-    let id = this.parseIdent(true);
+    case tt._yield:
+      if (this.state.inGenerator) this.unexpected();
 
-    //
-    if (this.options.features["es7.asyncFunctions"]) {
-      if (id.name === "await") {
-        if (this.inAsync) return this.parseAwait(node);
-      } else if (id.name === "async" && this.state.type === tt._function && !this.canInsertSemicolon()) {
+    case tt._do:
+      if (this.options.features["es7.doExpressions"]) {
+        let node = this.startNode();
         this.next();
-        return this.parseFunction(node, false, false, true);
-      } else if (canBeArrow && id.name === "async" && this.state.type === tt.name) {
-        var params = [this.parseIdent()];
-        this.expect(tt.arrow);
-        // var foo = bar => {};
-        return this.parseArrowExpression(node, params, true);
+        var oldInFunction = this.state.inFunction;
+        var oldLabels = this.state.labels;
+        this.state.labels = [];
+        this.state.inFunction = false;
+        node.body = this.parseBlock();
+        this.state.inFunction = oldInFunction;
+        this.state.labels = oldLabels;
+        return this.finishNode(node, "DoExpression");
       }
-    }
 
-    if (canBeArrow && !this.canInsertSemicolon() && this.eat(tt.arrow)) {
-      return this.parseArrowExpression(node, [id]);
-    }
+    case tt.name:
+      node = this.startNode();
+      let id = this.parseIdent(true);
 
-    return id;
+      //
+      if (this.options.features["es7.asyncFunctions"]) {
+        if (id.name === "await") {
+          if (this.inAsync) return this.parseAwait(node);
+        } else if (id.name === "async" && this.match(tt._function) && !this.canInsertSemicolon()) {
+          this.next();
+          return this.parseFunction(node, false, false, true);
+        } else if (canBeArrow && id.name === "async" && this.match(tt.name)) {
+          var params = [this.parseIdent()];
+          this.expect(tt.arrow);
+          // var foo = bar => {};
+          return this.parseArrowExpression(node, params, true);
+        }
+      }
 
-  case tt.regexp:
-    let value = this.state.value;
-    node = this.parseLiteral(value.value);
-    node.regex = {pattern: value.pattern, flags: value.flags};
-    return node;
+      if (canBeArrow && !this.canInsertSemicolon() && this.eat(tt.arrow)) {
+        return this.parseArrowExpression(node, [id]);
+      }
 
-  case tt.num: case tt.string:
-    return this.parseLiteral(this.state.value);
+      return id;
 
-  case tt._null: case tt._true: case tt._false:
-    node = this.startNode();
-    node.rawValue = node.value = this.state.type === tt._null ? null : this.state.type === tt._true;
-    node.raw = this.state.type.keyword;
-    this.next();
-    return this.finishNode(node, "Literal");
+    case tt.regexp:
+      let value = this.state.value;
+      node = this.parseLiteral(value.value);
+      node.regex = {pattern: value.pattern, flags: value.flags};
+      return node;
 
-  case tt.parenL:
-    return this.parseParenAndDistinguishExpression(null, null, canBeArrow);
+    case tt.num: case tt.string:
+      return this.parseLiteral(this.state.value);
 
-  case tt.bracketL:
-    node = this.startNode();
-    this.next();
-    // check whether this is array comprehension or regular array
-    if (this.options.features["es7.comprehensions"] && this.state.type === tt._for) {
-      return this.parseComprehension(node, false);
-    }
-    node.elements = this.parseExprList(tt.bracketR, true, true, refShorthandDefaultPos);
-    this.toReferencedList(node.elements);
-    return this.finishNode(node, "ArrayExpression");
+    case tt._null: case tt._true: case tt._false:
+      node = this.startNode();
+      node.rawValue = node.value = this.match(tt._null) ? null : this.match(tt._true);
+      node.raw = this.state.type.keyword;
+      this.next();
+      return this.finishNode(node, "Literal");
 
-  case tt.braceL:
-    return this.parseObj(false, refShorthandDefaultPos);
+    case tt.parenL:
+      return this.parseParenAndDistinguishExpression(null, null, canBeArrow);
 
-  case tt._function:
-    node = this.startNode();
-    this.next();
-    return this.parseFunction(node, false);
+    case tt.bracketL:
+      node = this.startNode();
+      this.next();
+      // check whether this is array comprehension or regular array
+      if (this.options.features["es7.comprehensions"] && this.match(tt._for)) {
+        return this.parseComprehension(node, false);
+      }
+      node.elements = this.parseExprList(tt.bracketR, true, true, refShorthandDefaultPos);
+      this.toReferencedList(node.elements);
+      return this.finishNode(node, "ArrayExpression");
 
-  case tt.at:
-    this.parseDecorators();
+    case tt.braceL:
+      return this.parseObj(false, refShorthandDefaultPos);
 
-  case tt._class:
-    node = this.startNode();
-    this.takeDecorators(node);
-    return this.parseClass(node, false);
+    case tt._function:
+      node = this.startNode();
+      this.next();
+      return this.parseFunction(node, false);
 
-  case tt._new:
-    return this.parseNew();
+    case tt.at:
+      this.parseDecorators();
 
-  case tt.backQuote:
-    return this.parseTemplate();
+    case tt._class:
+      node = this.startNode();
+      this.takeDecorators(node);
+      return this.parseClass(node, false);
 
-  case tt.doubleColon:
-    node = this.startNode();
-    this.next();
-    node.object = null;
-    let callee = node.callee = this.parseNoCallExpr();
-    if (callee.type === "MemberExpression") {
-      return this.finishNode(node, "BindExpression");
-    } else {
-      this.raise(callee.start, "Binding should be performed on object property.");
-    }
+    case tt._new:
+      return this.parseNew();
 
-  default:
-    this.unexpected();
+    case tt.backQuote:
+      return this.parseTemplate();
+
+    case tt.doubleColon:
+      node = this.startNode();
+      this.next();
+      node.object = null;
+      let callee = node.callee = this.parseNoCallExpr();
+      if (callee.type === "MemberExpression") {
+        return this.finishNode(node, "BindExpression");
+      } else {
+        this.raise(callee.start, "Binding should be performed on object property.");
+      }
+
+    default:
+      this.unexpected();
   }
 };
 
@@ -421,31 +421,31 @@ pp.parseParenAndDistinguishExpression = function (startPos, startLoc, canBeArrow
   let val;
   this.next();
 
-  if (this.options.features["es7.comprehensions"] && this.state.type === tt._for) {
+  if (this.options.features["es7.comprehensions"] && this.match(tt._for)) {
     return this.parseComprehension(this.startNodeAt(startPos, startLoc), true);
   }
 
   let innerStartPos = this.state.start, innerStartLoc = this.state.startLoc;
   let exprList = [], first = true;
   let refShorthandDefaultPos = {start: 0}, spreadStart, innerParenStart, optionalCommaStart;
-  while (this.state.type !== tt.parenR) {
+  while (!this.match(tt.parenR)) {
     if (first) {
       first = false;
     } else {
       this.expect(tt.comma);
-      if (this.state.type === tt.parenR && this.options.features["es7.trailingFunctionCommas"]) {
+      if (this.match(tt.parenR) && this.options.features["es7.trailingFunctionCommas"]) {
         optionalCommaStart = this.state.start;
         break;
       }
     }
 
-    if (this.state.type === tt.ellipsis) {
+    if (this.match(tt.ellipsis)) {
       let spreadNodeStartPos = this.state.start, spreadNodeStartLoc = this.state.startLoc;
       spreadStart = this.state.start;
       exprList.push(this.parseParenItem(this.parseRest(), spreadNodeStartLoc, spreadNodeStartPos));
       break;
     } else {
-      if (this.state.type === tt.parenL && !innerParenStart) {
+      if (this.match(tt.parenL) && !innerParenStart) {
         innerParenStart = this.state.start;
       }
       exprList.push(this.parseMaybeAssign(false, refShorthandDefaultPos, this.parseParenItem));
@@ -528,7 +528,7 @@ pp.parseTemplateElement = function () {
     cooked: this.state.value
   };
   this.next();
-  elem.tail = this.state.type === tt.backQuote;
+  elem.tail = this.match(tt.backQuote);
   return this.finishNode(elem, "TemplateElement");
 };
 
@@ -560,10 +560,10 @@ pp.parseObj = function (isPattern, refShorthandDefaultPos) {
       first = false;
     } else {
       this.expect(tt.comma);
-      if (this.afterTrailingComma(tt.braceR)) break;
+      if (this.eat(tt.braceR)) break;
     }
 
-    while (this.state.type === tt.at) {
+    while (this.match(tt.at)) {
       decorators.push(this.parseDecorator());
     }
 
@@ -572,7 +572,7 @@ pp.parseObj = function (isPattern, refShorthandDefaultPos) {
       prop.decorators = decorators;
       decorators = [];
     }
-    if (this.options.features["es7.objectRestSpread"] && this.state.type === tt.ellipsis) {
+    if (this.options.features["es7.objectRestSpread"] && this.match(tt.ellipsis)) {
       prop = this.parseSpread();
       prop.type = "SpreadProperty";
       node.properties.push(prop);
@@ -589,7 +589,7 @@ pp.parseObj = function (isPattern, refShorthandDefaultPos) {
     if (this.options.features["es7.asyncFunctions"] && this.isContextual("async")) {
       if (isGenerator || isPattern) this.unexpected();
       var asyncId = this.parseIdent();
-      if (this.state.type === tt.colon || this.state.type === tt.parenL) {
+      if (this.match(tt.colon) || this.match(tt.parenL)) {
         prop.key = asyncId;
       } else {
         isAsync = true;
@@ -612,12 +612,12 @@ pp.parseObjPropValue = function (prop, startPos, startLoc, isGenerator, isAsync,
   if (this.eat(tt.colon)) {
     prop.value = isPattern ? this.parseMaybeDefault(this.state.start, this.state.startLoc) : this.parseMaybeAssign(false, refShorthandDefaultPos);
     prop.kind = "init";
-  } else if (this.state.type === tt.parenL) {
+  } else if (this.match(tt.parenL)) {
     if (isPattern) this.unexpected();
     prop.kind = "init";
     prop.method = true;
     prop.value = this.parseMethod(isGenerator, isAsync);
-  } else if (!prop.computed && prop.key.type === "Identifier" && (prop.key.name === "get" || prop.key.name === "set") && (this.state.type !== tt.comma && this.state.type !== tt.braceR)) {
+  } else if (!prop.computed && prop.key.type === "Identifier" && (prop.key.name === "get" || prop.key.name === "set") && (!this.match(tt.comma) && !this.match(tt.braceR))) {
     if (isGenerator || isAsync || isPattern) this.unexpected();
     prop.kind = prop.key.name;
     this.parsePropertyName(prop);
@@ -638,7 +638,7 @@ pp.parseObjPropValue = function (prop, startPos, startLoc, isGenerator, isAsync,
             (!this.options.allowReserved && this.isReservedWord(prop.key.name)))
           this.raise(prop.key.start, "Binding " + prop.key.name);
       prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key.__clone());
-    } else if (this.state.type === tt.eq && refShorthandDefaultPos) {
+    } else if (this.match(tt.eq) && refShorthandDefaultPos) {
       if (!refShorthandDefaultPos.start)
         refShorthandDefaultPos.start = this.state.start;
       prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key.__clone());
@@ -659,7 +659,7 @@ pp.parsePropertyName = function (prop) {
     return prop.key;
   } else {
     prop.computed = false;
-    return prop.key = (this.state.type === tt.num || this.state.type === tt.string) ? this.parseExprAtom() : this.parseIdent(true);
+    return prop.key = (this.match(tt.num) || this.match(tt.string)) ? this.parseExprAtom() : this.parseIdent(true);
   }
 };
 
@@ -698,7 +698,7 @@ pp.parseArrowExpression = function (node, params, isAsync) {
 // Parse function body and check parameters.
 
 pp.parseFunctionBody = function (node, allowExpression) {
-  let isExpression = allowExpression && this.state.type !== tt.braceL;
+  let isExpression = allowExpression && !this.match(tt.braceL);
 
   var oldInAsync = this.inAsync;
   this.inAsync = node.async;
@@ -745,7 +745,7 @@ pp.parseExprList = function (close, allowTrailingComma, allowEmpty, refShorthand
       first = false;
     } else {
       this.expect(tt.comma);
-      if (allowTrailingComma && this.afterTrailingComma(close)) break;
+      if (allowTrailingComma && this.eat(close)) break;
     }
 
     elts.push(this.parseExprListItem(allowEmpty, refShorthandDefaultPos));
@@ -755,9 +755,9 @@ pp.parseExprList = function (close, allowTrailingComma, allowEmpty, refShorthand
 
 pp.parseExprListItem = function (allowEmpty, refShorthandDefaultPos) {
   let elt;
-  if (allowEmpty && this.state.type === tt.comma) {
+  if (allowEmpty && this.match(tt.comma)) {
     elt = null;
-  } else if (this.state.type === tt.ellipsis) {
+  } else if (this.match(tt.ellipsis)) {
     elt = this.parseSpread(refShorthandDefaultPos);
   } else {
     elt = this.parseMaybeAssign(false, refShorthandDefaultPos);
@@ -771,7 +771,7 @@ pp.parseExprListItem = function (allowEmpty, refShorthandDefaultPos) {
 
 pp.parseIdent = function (liberal) {
   let node = this.startNode();
-  if (this.state.type === tt.name) {
+  if (this.match(tt.name)) {
     if (!liberal &&
         ((!this.options.allowReserved && this.isReservedWord(this.state.value)) ||
          (this.strict && reservedWords.strict(this.state.value))))
@@ -802,7 +802,7 @@ pp.parseAwait = function (node) {
 pp.parseYield = function () {
   let node = this.startNode();
   this.next();
-  if (this.state.type === tt.semi || this.canInsertSemicolon() || (this.state.type !== tt.star && !this.state.type.startsExpr)) {
+  if (this.match(tt.semi) || this.canInsertSemicolon() || (!this.match(tt.star) && !this.state.type.startsExpr)) {
     node.delegate = false;
     node.argument = null;
   } else {
@@ -816,7 +816,7 @@ pp.parseYield = function () {
 
 pp.parseComprehension = function (node, isGenerator) {
   node.blocks = [];
-  while (this.state.type === tt._for) {
+  while (this.match(tt._for)) {
     let block = this.startNode();
     this.next();
     this.expect(tt.parenL);
diff --git a/packages/babylon/src/parser/lval.js b/packages/babylon/src/parser/lval.js
index 68fd6c1252..265aa90cf0 100644
--- a/packages/babylon/src/parser/lval.js
+++ b/packages/babylon/src/parser/lval.js
@@ -92,7 +92,7 @@ pp.parseSpread = function (refShorthandDefaultPos) {
 pp.parseRest = function () {
   let node = this.startNode();
   this.next();
-  node.argument = this.state.type === tt.name || this.state.type === tt.bracketL ? this.parseBindingAtom() : this.unexpected();
+  node.argument = this.match(tt.name) || this.match(tt.bracketL) ? this.parseBindingAtom() : this.unexpected();
   return this.finishNode(node, "RestElement");
 };
 
@@ -122,11 +122,11 @@ pp.parseBindingList = function (close, allowEmpty, allowTrailingComma) {
   while (!this.eat(close)) {
     if (first) first = false;
     else this.expect(tt.comma);
-    if (allowEmpty && this.state.type === tt.comma) {
+    if (allowEmpty && this.match(tt.comma)) {
       elts.push(null);
-    } else if (allowTrailingComma && this.afterTrailingComma(close)) {
+    } else if (allowTrailingComma && this.eat(close)) {
       break;
-    } else if (this.state.type === tt.ellipsis) {
+    } else if (this.match(tt.ellipsis)) {
       elts.push(this.parseAssignableListItemTypes(this.parseRest()));
       this.expect(close);
       break;
diff --git a/packages/babylon/src/parser/statement.js b/packages/babylon/src/parser/statement.js
index 4d63b2a0f2..730cf0c2a4 100644
--- a/packages/babylon/src/parser/statement.js
+++ b/packages/babylon/src/parser/statement.js
@@ -16,7 +16,7 @@ pp.parseTopLevel = function (file, program) {
   program.body = [];
 
   let first = true;
-  while (this.state.type !== tt.eof) {
+  while (!this.match(tt.eof)) {
     let stmt = this.parseStatement(true, true);
     program.body.push(stmt);
     if (first) {
@@ -43,7 +43,7 @@ const loopLabel = {kind: "loop"}, switchLabel = {kind: "switch"};
 // does not help.
 
 pp.parseStatement = function (declaration, topLevel) {
-  if (this.state.type === tt.at) {
+  if (this.match(tt.at)) {
     this.parseDecorators(true);
   }
 
@@ -94,7 +94,7 @@ pp.parseStatement = function (declaration, topLevel) {
         // peek ahead and see if next token is a function
         var state = this.state.clone();
         this.next();
-        if (this.state.type === tt._function && !this.canInsertSemicolon()) {
+        if (this.match(tt._function) && !this.canInsertSemicolon()) {
           this.expect(tt._function);
           return this.parseFunction(node, true, false, true);
         } else {
@@ -126,15 +126,15 @@ pp.takeDecorators = function (node) {
 };
 
 pp.parseDecorators = function (allowExport) {
-  while (this.state.type === tt.at) {
+  while (this.match(tt.at)) {
     this.state.decorators.push(this.parseDecorator());
   }
 
-  if (allowExport && this.state.type === tt._export) {
+  if (allowExport && this.match(tt._export)) {
     return;
   }
 
-  if (this.state.type !== tt._class) {
+  if (!this.match(tt._class)) {
     this.raise(this.state.start, "Leading decorators must be attached to a class declaration");
   }
 };
@@ -153,9 +153,9 @@ pp.parseBreakContinueStatement = function (node, keyword) {
   let isBreak = keyword === "break";
   this.next();
 
-  if (this.eat(tt.semi) || this.insertSemicolon()) {
+  if (this.eat(tt.semi) || this.canInsertSemicolon()) {
     node.label = null;
-  } else if (this.state.type !== tt.name) {
+  } else if (!this.match(tt.name)) {
     this.unexpected();
   } else {
     node.label = this.parseIdent();
@@ -205,16 +205,16 @@ pp.parseForStatement = function (node) {
   this.state.labels.push(loopLabel);
   this.expect(tt.parenL);
 
-  if (this.state.type === tt.semi) {
+  if (this.match(tt.semi)) {
     return this.parseFor(node, null);
   }
 
-  if (this.state.type === tt._var || this.state.type === tt._let || this.state.type === tt._const) {
+  if (this.match(tt._var) || this.match(tt._let) || this.match(tt._const)) {
     let init = this.startNode(), varKind = this.state.type;
     this.next();
     this.parseVar(init, true, varKind);
     this.finishNode(init, "VariableDeclaration");
-    if ((this.state.type === tt._in || this.isContextual("of")) && init.declarations.length === 1 &&
+    if ((this.match(tt._in) || this.isContextual("of")) && init.declarations.length === 1 &&
         !(varKind !== tt._var && init.declarations[0].init))
       return this.parseForIn(node, init);
     return this.parseFor(node, init);
@@ -222,7 +222,7 @@ pp.parseForStatement = function (node) {
 
   let refShorthandDefaultPos = {start: 0};
   let init = this.parseExpression(true, refShorthandDefaultPos);
-  if (this.state.type === tt._in || this.isContextual("of")) {
+  if (this.match(tt._in) || this.isContextual("of")) {
     this.toAssignable(init);
     this.checkLVal(init);
     return this.parseForIn(node, init);
@@ -256,7 +256,7 @@ pp.parseReturnStatement = function (node) {
   // optional arguments, we eagerly look for a semicolon or the
   // possibility to insert one.
 
-  if (this.eat(tt.semi) || this.insertSemicolon()) {
+  if (this.eat(tt.semi) || this.canInsertSemicolon()) {
     node.argument = null;
   } else {
     node.argument = this.parseExpression();
@@ -277,9 +277,9 @@ pp.parseSwitchStatement = function (node) {
   // nodes. `cur` is used to keep the node that we are currently
   // adding statements to.
 
-  for (var cur, sawDefault; this.state.type !== tt.braceR; ) {
-    if (this.state.type === tt._case || this.state.type === tt._default) {
-      let isCase = this.state.type === tt._case;
+  for (var cur, sawDefault; !this.match(tt.braceR); ) {
+    if (this.match(tt._case) || this.match(tt._default)) {
+      let isCase = this.match(tt._case);
       if (cur) this.finishNode(cur, "SwitchCase");
       node.cases.push(cur = this.startNode());
       cur.consequent = [];
@@ -320,7 +320,7 @@ pp.parseTryStatement = function (node) {
   this.next();
   node.block = this.parseBlock();
   node.handler = null;
-  if (this.state.type === tt._catch) {
+  if (this.match(tt._catch)) {
     let clause = this.startNode();
     this.next();
     this.expect(tt.parenL);
@@ -377,7 +377,7 @@ pp.parseLabeledStatement = function (node, maybeName, expr) {
     }
   }
 
-  let kind = this.state.type.isLoop ? "loop" : this.state.type === tt._switch ? "switch" : null;
+  let kind = this.state.type.isLoop ? "loop" : this.match(tt._switch) ? "switch" : null;
   for (let i = this.state.labels.length - 1; i >= 0; i--) {
     let label = this.state.labels[i];
     if (label.statementStart === node.start) {
@@ -429,9 +429,9 @@ pp.parseBlock = function (allowStrict) {
 pp.parseFor = function (node, init) {
   node.init = init;
   this.expect(tt.semi);
-  node.test = this.state.type === tt.semi ? null : this.parseExpression();
+  node.test = this.match(tt.semi) ? null : this.parseExpression();
   this.expect(tt.semi);
-  node.update = this.state.type === tt.parenR ? null : this.parseExpression();
+  node.update = this.match(tt.parenR) ? null : this.parseExpression();
   this.expect(tt.parenR);
   node.body = this.parseStatement(false);
   this.state.labels.pop();
@@ -442,7 +442,7 @@ pp.parseFor = function (node, init) {
 // same from parser's perspective.
 
 pp.parseForIn = function (node, init) {
-  let type = this.state.type === tt._in ? "ForInStatement" : "ForOfStatement";
+  let type = this.match(tt._in) ? "ForInStatement" : "ForOfStatement";
   this.next();
   node.left = init;
   node.right = this.parseExpression();
@@ -462,9 +462,9 @@ pp.parseVar = function (node, isFor, kind) {
     this.parseVarHead(decl);
     if (this.eat(tt.eq)) {
       decl.init = this.parseMaybeAssign(isFor);
-    } else if (kind === tt._const && !(this.state.type === tt._in || this.isContextual("of"))) {
+    } else if (kind === tt._const && !(this.match(tt._in) || this.isContextual("of"))) {
       this.unexpected();
-    } else if (decl.id.type !== "Identifier" && !(isFor && (this.state.type === tt._in || this.isContextual("of")))) {
+    } else if (decl.id.type !== "Identifier" && !(isFor && (this.match(tt._in) || this.isContextual("of")))) {
       this.raise(this.state.lastTokEnd, "Complex binding patterns require an initialization value");
     } else {
       decl.init = null;
@@ -487,7 +487,7 @@ pp.parseFunction = function (node, isStatement, allowExpressionBody, isAsync) {
   this.initFunction(node, isAsync);
   node.generator = this.eat(tt.star);
 
-  if (isStatement || this.state.type === tt.name) {
+  if (isStatement || this.match(tt.name)) {
     node.id = this.parseIdent();
   }
 
@@ -515,7 +515,7 @@ pp.parseClass = function (node, isStatement) {
   let decorators = [];
   while (!this.eat(tt.braceR)) {
     if (this.eat(tt.semi)) continue;
-    if (this.state.type === tt.at) {
+    if (this.match(tt.at)) {
       decorators.push(this.parseDecorator());
       continue;
     }
@@ -524,10 +524,10 @@ pp.parseClass = function (node, isStatement) {
       method.decorators = decorators;
       decorators = [];
     }
-    let isMaybeStatic = this.state.type === tt.name && this.state.value === "static";
+    let isMaybeStatic = this.match(tt.name) && this.state.value === "static";
     var isGenerator = this.eat(tt.star), isAsync = false;
     this.parsePropertyName(method);
-    method.static = isMaybeStatic && this.state.type !== tt.parenL;
+    method.static = isMaybeStatic && !this.match(tt.parenL);
     if (method.static) {
       if (isGenerator) this.unexpected();
       isGenerator = this.eat(tt.star);
@@ -537,7 +537,7 @@ pp.parseClass = function (node, isStatement) {
       classBody.body.push(this.parseClassProperty(method));
       continue;
     }
-    if (this.options.features["es7.asyncFunctions"] && this.state.type !== tt.parenL &&
+    if (this.options.features["es7.asyncFunctions"] && !this.match(tt.parenL) &&
         !method.computed && method.key.type === "Identifier" && method.key.name === "async") {
       isAsync = true;
       this.parsePropertyName(method);
@@ -546,7 +546,7 @@ pp.parseClass = function (node, isStatement) {
     method.kind = "method";
     if (!method.computed) {
       let {key} = method;
-      if (!isAsync && !isGenerator && key.type === "Identifier" && this.state.type !== tt.parenL && (key.name === "get" || key.name === "set")) {
+      if (!isAsync && !isGenerator && key.type === "Identifier" && !this.match(tt.parenL) && (key.name === "get" || key.name === "set")) {
         isGetSet = true;
         method.kind = key.name;
         key = this.parsePropertyName(method);
@@ -587,11 +587,11 @@ pp.parseClass = function (node, isStatement) {
 };
 
 pp.isClassProperty = function () {
-  return this.state.type === tt.eq || (this.state.type === tt.semi || this.canInsertSemicolon());
+  return this.match(tt.eq) || (this.match(tt.semi) || this.canInsertSemicolon());
 };
 
 pp.parseClassProperty = function (node) {
-  if (this.state.type === tt.eq) {
+  if (this.match(tt.eq)) {
     if (!this.options.features["es7.classProperties"]) this.unexpected();
     this.next();
     node.value = this.parseMaybeAssign();
@@ -608,7 +608,7 @@ pp.parseClassMethod = function (classBody, method, isGenerator, isAsync) {
 };
 
 pp.parseClassId = function (node, isStatement) {
-  node.id = this.state.type === tt.name ? this.parseIdent() : isStatement ? this.unexpected() : null;
+  node.id = this.match(tt.name) ? this.parseIdent() : isStatement ? this.unexpected() : null;
 };
 
 pp.parseClassSuper = function (node) {
@@ -620,7 +620,7 @@ pp.parseClassSuper = function (node) {
 pp.parseExport = function (node) {
   this.next();
   // export * from '...'
-  if (this.state.type === tt.star) {
+  if (this.match(tt.star)) {
     let specifier = this.startNode();
     this.next();
     if (this.options.features["es7.exportExtensions"] && this.eatContextual("as")) {
@@ -636,7 +636,7 @@ pp.parseExport = function (node) {
     let specifier = this.startNode();
     specifier.exported = this.parseIdent(true);
     node.specifiers = [this.finishNode(specifier, "ExportDefaultSpecifier")];
-    if (this.state.type === tt.comma && this.lookahead().type === tt.star) {
+    if (this.match(tt.comma) && this.lookahead().type === tt.star) {
       this.expect(tt.comma);
       let specifier = this.startNode();
       this.expect(tt.star);
@@ -668,7 +668,7 @@ pp.parseExport = function (node) {
     node.declaration = null;
     node.specifiers = this.parseExportSpecifiers();
     if (this.eatContextual("from")) {
-      node.source = this.state.type === tt.string ? this.parseExprAtom() : this.unexpected();
+      node.source = this.match(tt.string) ? this.parseExprAtom() : this.unexpected();
     } else {
       node.source = null;
     }
@@ -679,11 +679,11 @@ pp.parseExport = function (node) {
 };
 
 pp.isExportDefaultSpecifier = function () {
-  if (this.state.type === tt.name) {
+  if (this.match(tt.name)) {
     return this.state.value !== "type" && this.state.value !== "async";
   }
 
-  if (this.state.type !== tt._default) {
+  if (!this.match(tt._default)) {
     return false;
   }
 
@@ -699,7 +699,7 @@ pp.parseExportSpecifiersMaybe = function (node) {
 
 pp.parseExportFrom = function (node) {
   this.expectContextual("from");
-  node.source = this.state.type === tt.string ? this.parseExprAtom() : this.unexpected();
+  node.source = this.match(tt.string) ? this.parseExprAtom() : this.unexpected();
   this.semicolon();
   this.checkExport(node);
 };
@@ -730,11 +730,11 @@ pp.parseExportSpecifiers = function () {
       first = false;
     } else {
       this.expect(tt.comma);
-      if (this.afterTrailingComma(tt.braceR)) break;
+      if (this.eat(tt.braceR)) break;
     }
 
     let node = this.startNode();
-    node.local = this.parseIdent(this.state.type === tt._default);
+    node.local = this.parseIdent(this.match(tt._default));
     node.exported = this.eatContextual("as") ? this.parseIdent(true) : node.local.__clone();
     nodes.push(this.finishNode(node, "ExportSpecifier"));
   }
@@ -748,14 +748,14 @@ pp.parseImport = function (node) {
   this.next();
 
   // import '...'
-  if (this.state.type === tt.string) {
+  if (this.match(tt.string)) {
     node.specifiers = [];
     node.source = this.parseExprAtom();
   } else {
     node.specifiers = [];
     this.parseImportSpecifiers(node);
     this.expectContextual("from");
-    node.source = this.state.type === tt.string ? this.parseExprAtom() : this.unexpected();
+    node.source = this.match(tt.string) ? this.parseExprAtom() : this.unexpected();
   }
   this.semicolon();
   return this.finishNode(node, "ImportDeclaration");
@@ -765,14 +765,14 @@ pp.parseImport = function (node) {
 
 pp.parseImportSpecifiers = function (node) {
   var first = true;
-  if (this.state.type === tt.name) {
+  if (this.match(tt.name)) {
     // import defaultObj, { x, y as z } from '...'
     var startPos = this.state.start, startLoc = this.state.startLoc;
     node.specifiers.push(this.parseImportSpecifierDefault(this.parseIdent(), startPos, startLoc));
     if (!this.eat(tt.comma)) return;
   }
 
-  if (this.state.type === tt.star) {
+  if (this.match(tt.star)) {
     let specifier = this.startNode();
     this.next();
     this.expectContextual("as");
@@ -788,7 +788,7 @@ pp.parseImportSpecifiers = function (node) {
       first = false;
     } else {
       this.expect(tt.comma);
-      if (this.afterTrailingComma(tt.braceR)) break;
+      if (this.eat(tt.braceR)) break;
     }
 
     let specifier = this.startNode();
diff --git a/packages/babylon/src/parser/util.js b/packages/babylon/src/parser/util.js
index 8c6c09017d..51ca0bdc6f 100644
--- a/packages/babylon/src/parser/util.js
+++ b/packages/babylon/src/parser/util.js
@@ -12,22 +12,10 @@ pp.isUseStrict = function (stmt) {
   return stmt.type === "ExpressionStatement" && stmt.expression.type === "Literal" && stmt.expression.raw.slice(1, -1) === "use strict";
 };
 
-// Predicate that tests whether the next token is of the given
-// type, and if yes, consumes it as a side effect.
-
-pp.eat = function (type) {
-  if (this.state.type === type) {
-    this.next();
-    return true;
-  } else {
-    return false;
-  }
-};
-
 // TODO
 
 pp.isRelational = function (op) {
-  return this.state.type === tt.relational && this.state.value === op;
+  return this.match(tt.relational) && this.state.value === op;
 };
 
 // TODO
@@ -43,7 +31,7 @@ pp.expectRelational = function (op) {
 // Tests whether parsed token is a contextual keyword.
 
 pp.isContextual = function (name) {
-  return this.state.type === tt.name && this.state.value === name;
+  return this.match(tt.name) && this.state.value === name;
 };
 
 // Consumes contextual keyword if possible.
@@ -61,29 +49,16 @@ pp.expectContextual = function (name) {
 // Test whether a semicolon can be inserted at the current position.
 
 pp.canInsertSemicolon = function () {
-  return this.state.type === tt.eof ||
-    this.state.type === tt.braceR ||
+  return this.match(tt.eof) ||
+    this.match(tt.braceR) ||
     lineBreak.test(this.input.slice(this.state.lastTokEnd, this.state.start));
 };
 
-pp.insertSemicolon = function () {
-  if (this.canInsertSemicolon()) {
-    return true;
-  }
-};
-
 // Consume a semicolon, or, failing that, see if we are allowed to
 // pretend that there is a semicolon at this position.
 
 pp.semicolon = function () {
-  if (!this.eat(tt.semi) && !this.insertSemicolon()) this.unexpected();
-};
-
-pp.afterTrailingComma = function (tokType) {
-  if (this.state.type === tokType) {
-    this.next();
-    return true;
-  }
+  if (!this.eat(tt.semi) && !this.canInsertSemicolon()) this.unexpected();
 };
 
 // Expect a token of a given type. If found, consume it, otherwise,
diff --git a/packages/babylon/src/plugins/flow.js b/packages/babylon/src/plugins/flow.js
index 7b45b70880..2f1c190ae5 100644
--- a/packages/babylon/src/plugins/flow.js
+++ b/packages/babylon/src/plugins/flow.js
@@ -50,11 +50,11 @@ pp.flowParseDeclareFunction = function (node) {
 };
 
 pp.flowParseDeclare = function (node) {
-  if (this.state.type === tt._class) {
+  if (this.match(tt._class)) {
     return this.flowParseDeclareClass(node);
-  } else if (this.state.type === tt._function) {
+  } else if (this.match(tt._function)) {
     return this.flowParseDeclareFunction(node);
-  } else if (this.state.type === tt._var) {
+  } else if (this.match(tt._var)) {
     return this.flowParseDeclareVariable(node);
   } else if (this.isContextual("module")) {
     return this.flowParseDeclareModule(node);
@@ -73,7 +73,7 @@ pp.flowParseDeclareVariable = function (node) {
 pp.flowParseDeclareModule = function (node) {
   this.next();
 
-  if (this.state.type === tt.string) {
+  if (this.match(tt.string)) {
     node.id = this.parseExprAtom();
   } else {
     node.id = this.parseIdent();
@@ -82,7 +82,7 @@ pp.flowParseDeclareModule = function (node) {
   var bodyNode = node.body = this.startNode();
   var body = bodyNode.body = [];
   this.expect(tt.braceL);
-  while (this.state.type !== tt.braceR) {
+  while (!this.match(tt.braceR)) {
     var node2 = this.startNode();
 
     // todo: declare check
@@ -193,7 +193,7 @@ pp.flowParseTypeParameterInstantiation = function () {
 };
 
 pp.flowParseObjectPropertyKey = function () {
-  return (this.state.type === tt.num || this.state.type === tt.string) ? this.parseExprAtom() : this.parseIdent(true);
+  return (this.match(tt.num) || this.match(tt.string)) ? this.parseExprAtom() : this.parseIdent(true);
 };
 
 pp.flowParseObjectTypeIndexer = function (node, isStatic) {
@@ -219,9 +219,9 @@ pp.flowParseObjectTypeMethodish = function (node) {
   }
 
   this.expect(tt.parenL);
-  while (this.state.type === tt.name) {
+  while (this.match(tt.name)) {
     node.params.push(this.flowParseFunctionTypeParam());
-    if (this.state.type !== tt.parenR) {
+    if (!this.match(tt.parenR)) {
       this.expect(tt.comma);
     }
   }
@@ -266,7 +266,7 @@ pp.flowParseObjectType = function (allowStatic) {
 
   this.expect(tt.braceL);
 
-  while (this.state.type !== tt.braceR) {
+  while (!this.match(tt.braceR)) {
     var startPos = this.state.start, startLoc = this.state.startLoc;
     node = this.startNode();
     if (allowStatic && this.isContextual("static")) {
@@ -274,17 +274,17 @@ pp.flowParseObjectType = function (allowStatic) {
       isStatic = true;
     }
 
-    if (this.state.type === tt.bracketL) {
+    if (this.match(tt.bracketL)) {
       nodeStart.indexers.push(this.flowParseObjectTypeIndexer(node, isStatic));
-    } else if (this.state.type === tt.parenL || this.isRelational("<")) {
+    } else if (this.match(tt.parenL) || this.isRelational("<")) {
       nodeStart.callProperties.push(this.flowParseObjectTypeCallProperty(node, allowStatic));
     } else {
-      if (isStatic && this.state.type === tt.colon) {
+      if (isStatic && this.match(tt.colon)) {
         propertyKey = this.parseIdent();
       } else {
         propertyKey = this.flowParseObjectPropertyKey();
       }
-      if (this.isRelational("<") || this.state.type === tt.parenL) {
+      if (this.isRelational("<") || this.match(tt.parenL)) {
         // This is a method property
         nodeStart.properties.push(this.flowParseObjectTypeMethod(startPos, startLoc, isStatic, propertyKey));
       } else {
@@ -307,7 +307,7 @@ pp.flowParseObjectType = function (allowStatic) {
 };
 
 pp.flowObjectTypeSemicolon = function () {
-  if (!this.eat(tt.semi) && !this.eat(tt.comma) && this.state.type !== tt.braceR) {
+  if (!this.eat(tt.semi) && !this.eat(tt.comma) && !this.match(tt.braceR)) {
     this.unexpected();
   }
 };
@@ -344,9 +344,9 @@ pp.flowParseTupleType = function () {
   node.types = [];
   this.expect(tt.bracketL);
   // We allow trailing commas
-  while (this.state.pos < this.input.length && this.state.type !== tt.bracketR) {
+  while (this.state.pos < this.input.length && !this.match(tt.bracketR)) {
     node.types.push(this.flowParseType());
-    if (this.state.type === tt.bracketR) break;
+    if (this.match(tt.bracketR)) break;
     this.expect(tt.comma);
   }
   this.expect(tt.bracketR);
@@ -367,9 +367,9 @@ pp.flowParseFunctionTypeParam = function () {
 
 pp.flowParseFunctionTypeParams = function () {
   var ret = { params: [], rest: null };
-  while (this.state.type === tt.name) {
+  while (this.match(tt.name)) {
     ret.params.push(this.flowParseFunctionTypeParam());
-    if (this.state.type !== tt.parenR) {
+    if (!this.match(tt.parenR)) {
       this.expect(tt.comma);
     }
   }
@@ -445,8 +445,8 @@ pp.flowParsePrimaryType = function () {
       this.next();
 
       // Check to see if this is actually a grouped type
-      if (this.state.type !== tt.parenR && this.state.type !== tt.ellipsis) {
-        if (this.state.type === tt.name) {
+      if (!this.match(tt.parenR) && !this.match(tt.ellipsis)) {
+        if (this.match(tt.name)) {
           var token = this.lookahead().type;
           isGroupedType = token !== tt.question && token !== tt.colon;
         } else {
@@ -511,7 +511,7 @@ pp.flowParsePrimaryType = function () {
 pp.flowParsePostfixType = function () {
   var node = this.startNode();
   var type = node.elementType = this.flowParsePrimaryType();
-  if (this.state.type === tt.bracketL) {
+  if (this.match(tt.bracketL)) {
     this.expect(tt.bracketL);
     this.expect(tt.bracketR);
     return this.finishNode(node, "ArrayTypeAnnotation");
@@ -573,7 +573,7 @@ pp.flowParseTypeAnnotatableIdentifier = function (requireTypeAnnotation, canBeOp
     isOptionalParam = true;
   }
 
-  if (requireTypeAnnotation || this.state.type === tt.colon) {
+  if (requireTypeAnnotation || this.match(tt.colon)) {
     ident.typeAnnotation = this.flowParseTypeAnnotation();
     this.finishNode(ident, ident.type);
   }
@@ -590,7 +590,7 @@ export default function (instance) {
   // function name(): string {}
   instance.extend("parseFunctionBody", function (inner) {
     return function (node, allowExpression) {
-      if (this.state.type === tt.colon && !allowExpression) {
+      if (this.match(tt.colon) && !allowExpression) {
         // if allowExpression is true then we're parsing an arrow function and if
         // there's a return type then it's been handled elsewhere
         node.returnType = this.flowParseTypeAnnotation();
@@ -603,7 +603,7 @@ export default function (instance) {
   instance.extend("parseStatement", function (inner) {
     return function (declaration, topLevel) {
       // strict mode handling of `interface` since it's a reserved word
-      if (this.strict && this.state.type === tt.name && this.state.value === "interface") {
+      if (this.strict && this.match(tt.name) && this.state.value === "interface") {
         var node = this.startNode();
         this.next();
         return this.flowParseInterface(node);
@@ -617,10 +617,10 @@ export default function (instance) {
     return function (node, expr) {
       if (expr.type === "Identifier") {
         if (expr.name === "declare") {
-          if (this.state.type === tt._class || this.state.type === tt.name || this.state.type === tt._function || this.state.type === tt._var) {
+          if (this.match(tt._class) || this.match(tt.name) || this.match(tt._function) || this.match(tt._var)) {
             return this.flowParseDeclare(node);
           }
-        } else if (this.state.type === tt.name) {
+        } else if (this.match(tt.name)) {
           if (expr.name === "interface") {
             return this.flowParseInterface(node);
           } else if (expr.name === "type") {
@@ -641,12 +641,12 @@ export default function (instance) {
 
   instance.extend("parseParenItem", function () {
     return function (node, startLoc, startPos, forceArrow?) {
-      if (this.state.type === tt.colon) {
+      if (this.match(tt.colon)) {
         var typeCastNode = this.startNodeAt(startLoc, startPos);
         typeCastNode.expression = node;
         typeCastNode.typeAnnotation = this.flowParseTypeAnnotation();
 
-        if (forceArrow && this.state.type !== tt.arrow) {
+        if (forceArrow && !this.match(tt.arrow)) {
           this.unexpected();
         }
 
@@ -735,7 +735,7 @@ export default function (instance) {
     return function (allowEmpty, refShorthandDefaultPos) {
       var container = this.startNode();
       var node = inner.call(this, allowEmpty, refShorthandDefaultPos);
-      if (this.state.type === tt.colon) {
+      if (this.match(tt.colon)) {
         container._exprListItem = true;
         container.expression = node;
         container.typeAnnotation = this.flowParseTypeAnnotation();
@@ -748,7 +748,7 @@ export default function (instance) {
 
   instance.extend("parseClassProperty", function (inner) {
     return function (node) {
-      if (this.state.type === tt.colon) {
+      if (this.match(tt.colon)) {
         node.typeAnnotation = this.flowParseTypeAnnotation();
       }
       return inner.call(this, node);
@@ -757,7 +757,7 @@ export default function (instance) {
 
   instance.extend("isClassProperty", function (inner) {
     return function () {
-      return this.state.type === tt.colon || inner.call(this);
+      return this.match(tt.colon) || inner.call(this);
     };
   });
 
@@ -801,7 +801,7 @@ export default function (instance) {
       var typeParameters;
       if (this.isRelational("<")) {
         typeParameters = this.flowParseTypeParameterDeclaration();
-        if (this.state.type !== tt.parenL) this.unexpected();
+        if (!this.match(tt.parenL)) this.unexpected();
       }
       inner.apply(this, arguments);
       prop.value.typeParameters = typeParameters;
@@ -813,7 +813,7 @@ export default function (instance) {
       if (this.eat(tt.question)) {
         param.optional = true;
       }
-      if (this.state.type === tt.colon) {
+      if (this.match(tt.colon)) {
         param.typeAnnotation = this.flowParseTypeAnnotation();
       }
       this.finishNode(param, param.type);
@@ -825,7 +825,7 @@ export default function (instance) {
     return function (node) {
       node.importKind = "value";
 
-      var kind = (this.state.type === tt._typeof ? "typeof" : (this.isContextual("type") ? "type" : null));
+      var kind = (this.match(tt._typeof) ? "typeof" : (this.isContextual("type") ? "type" : null));
       if (kind) {
         var lh = this.lookahead();
         if ((lh.type === tt.name && lh.value !== "from") || lh.type === tt.braceL || lh.type === tt.star) {
@@ -852,7 +852,7 @@ export default function (instance) {
   instance.extend("parseVarHead", function (inner) {
     return function (decl) {
       inner.call(this, decl);
-      if (this.state.type === tt.colon) {
+      if (this.match(tt.colon)) {
         decl.id.typeAnnotation = this.flowParseTypeAnnotation();
         this.finishNode(decl.id, decl.id.type);
       }
@@ -862,7 +862,7 @@ export default function (instance) {
   // var foo = (async (): number => {});
   instance.extend("parseAsyncArrowFromCallExpression", function (inner) {
     return function (node, call) {
-      if (this.state.type === tt.colon) {
+      if (this.match(tt.colon)) {
         node.returnType = this.flowParseTypeAnnotation();
       }
 
@@ -881,7 +881,7 @@ export default function (instance) {
         this.expect(tt.parenR);
 
         let node = this.startNodeAt(startPos, startLoc);
-        if (this.state.type === tt.colon) node.returnType = this.flowParseTypeAnnotation();
+        if (this.match(tt.colon)) node.returnType = this.flowParseTypeAnnotation();
         this.expect(tt.arrow);
         return this.parseArrowExpression(node, [], isAsync);
       } else {
@@ -890,7 +890,7 @@ export default function (instance) {
 
         var state = this.state.clone();
 
-        if (this.state.type === tt.colon) {
+        if (this.match(tt.colon)) {
           try {
             return this.parseParenItem(node, startPos, startLoc, true);
           } catch (err) {
diff --git a/packages/babylon/src/plugins/jsx/index.js b/packages/babylon/src/plugins/jsx/index.js
index b07e60fe3b..3ff0cc0c7c 100644
--- a/packages/babylon/src/plugins/jsx/index.js
+++ b/packages/babylon/src/plugins/jsx/index.js
@@ -186,7 +186,7 @@ function getQualifiedJSXName(object) {
 
 pp.jsxParseIdentifier = function() {
   var node = this.startNode();
-  if (this.state.type === tt.jsxName) {
+  if (this.match(tt.jsxName)) {
     node.name = this.state.value;
   } else if (this.state.type.keyword) {
     node.name = this.state.type.keyword;
@@ -268,7 +268,7 @@ pp.jsxParseEmptyExpression = function() {
 pp.jsxParseExpressionContainer = function() {
   var node = this.startNode();
   this.next();
-  if (this.state.type === tt.braceR) {
+  if (this.match(tt.braceR)) {
     node.expression = this.jsxParseEmptyExpression();
   } else {
     node.expression = this.parseExpression();
@@ -298,7 +298,7 @@ pp.jsxParseOpeningElementAt = function(startPos, startLoc) {
   var node = this.startNodeAt(startPos, startLoc);
   node.attributes = [];
   node.name = this.jsxParseElementName();
-  while (this.state.type !== tt.slash && this.state.type !== tt.jsxTagEnd) {
+  while (!this.match(tt.slash) && !this.match(tt.jsxTagEnd)) {
     node.attributes.push(this.jsxParseAttribute());
   }
   node.selfClosing = this.eat(tt.slash);
@@ -360,7 +360,7 @@ pp.jsxParseElementAt = function(startPos, startLoc) {
   node.openingElement = openingElement;
   node.closingElement = closingElement;
   node.children = children;
-  if (this.state.type === tt.relational && this.state.value === "<") {
+  if (this.match(tt.relational) && this.state.value === "<") {
     this.raise(this.state.start, "Adjacent JSX elements must be wrapped in an enclosing tag");
   }
   return this.finishNode(node, "JSXElement");
@@ -377,9 +377,9 @@ pp.jsxParseElement = function() {
 export default function(instance) {
   instance.extend("parseExprAtom", function(inner) {
     return function(refShortHandDefaultPos) {
-      if (this.state.type === tt.jsxText)
+      if (this.match(tt.jsxText))
         return this.parseLiteral(this.state.value);
-      else if (this.state.type === tt.jsxTagStart)
+      else if (this.match(tt.jsxTagStart))
         return this.jsxParseElement();
       else
         return inner.call(this, refShortHandDefaultPos);
@@ -414,13 +414,13 @@ export default function(instance) {
 
   instance.extend("updateContext", function(inner) {
     return function(prevType) {
-      if (this.state.type === tt.braceL) {
+      if (this.match(tt.braceL)) {
         var curContext = this.curContext();
         if (curContext === tc.j_oTag) this.state.context.push(tc.b_expr);
         else if (curContext === tc.j_expr) this.state.context.push(tc.b_tmpl);
         else inner.call(this, prevType);
         this.state.exprAllowed = true;
-      } else if (this.state.type === tt.slash && prevType === tt.jsxTagStart) {
+      } else if (this.match(tt.slash) && prevType === tt.jsxTagStart) {
         this.state.context.length -= 2; // do not consider JSX expr -> JSX open tag -> ... anymore
         this.state.context.push(tc.j_cTag); // reconsider as closing tag context
         this.state.exprAllowed = false;
diff --git a/packages/babylon/src/tokenizer/index.js b/packages/babylon/src/tokenizer/index.js
index 5d2a210f4e..f75f720a7f 100644
--- a/packages/babylon/src/tokenizer/index.js
+++ b/packages/babylon/src/tokenizer/index.js
@@ -71,6 +71,25 @@ export default class Tokenizer {
     this.nextToken();
   }
 
+  // TODO
+
+  eat(type) {
+    if (this.match(type)) {
+      this.next();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  // TODO
+
+  match(type) {
+    return this.state.type === type;
+  }
+
+  // TODO
+
   lookahead() {
     var old = this.state.clone();
     this.next();
@@ -84,7 +103,7 @@ export default class Tokenizer {
 
   setStrict(strict) {
     this.strict = strict;
-    if (this.state.type !== tt.num && this.state.type !== tt.string) return;
+    if (!this.match(tt.num) && !this.match(tt.string)) return;
     this.state.pos = this.state.start;
     while (this.state.pos < this.state.lineStart) {
       this.state.lineStart = this.input.lastIndexOf("\n", this.state.lineStart - 2) + 1;
@@ -610,7 +629,7 @@ export default class Tokenizer {
       if (this.state.pos >= this.input.length) this.raise(this.state.start, "Unterminated template");
       let ch = this.input.charCodeAt(this.state.pos);
       if (ch === 96 || ch === 36 && this.input.charCodeAt(this.state.pos + 1) === 123) { // '`', '${'
-        if (this.state.pos === this.state.start && this.state.type === tt.template) {
+        if (this.state.pos === this.state.start && this.match(tt.template)) {
           if (ch === 36) {
             this.state.pos += 2;
             return this.finishToken(tt.dollarBraceL);
diff --git a/packages/babylon/src/tokenizer/state.js b/packages/babylon/src/tokenizer/state.js
index 61204ad329..d73fbbc568 100644
--- a/packages/babylon/src/tokenizer/state.js
+++ b/packages/babylon/src/tokenizer/state.js
@@ -25,9 +25,9 @@ export default class State {
     this.comments = [];
 
     // Comment attachment store
-    this.bottomRightStack = [];
     this.trailingComments = [];
     this.leadingComments  = [];
+    this.commentStack     = [];
 
     // The current position of the tokenizer in the input.
     this.pos = this.lineStart = 0;