Stop mutating nodes (#5963)

* Stop mutating nodes

* Update tests

* linting

packages/babel-core/src/transformation/file/index.js

@@ -236,7 +236,6 @@ export default class File extends Store {
 
     if (t.isFunctionExpression(ref) && !ref.id) {
       ref.body._compact = true;
-      ref._generated = true;
       ref.id = uid;
       ref.type = "FunctionDeclaration";
       this.path.unshiftContainer("body", ref);

packages/babel-generator/src/generators/expressions.js

@@ -91,13 +91,6 @@ export function Decorator(node: Object) {
   this.newline();
 }
 
-function commaSeparatorNewline() {
-  this.token(",");
-  this.newline();
-
-  if (!this.endsWith("\n")) this.space();
-}
-
 export function CallExpression(node: Object) {
   this.print(node.callee, node);
 
@@ -105,23 +98,7 @@ export function CallExpression(node: Object) {
     this.token("?.");
   }
   this.token("(");
-
+  this.printList(node.arguments, node);
-  const isPrettyCall = node._prettyCall;
-
-  let separator;
-  if (isPrettyCall) {
-    separator = commaSeparatorNewline;
-    this.newline();
-    this.indent();
-  }
-
-  this.printList(node.arguments, node, { separator });
-
-  if (isPrettyCall) {
-    this.newline();
-    this.dedent();
-  }
-
   this.token(")");
 }
 

packages/babel-helper-builder-react-jsx/src/index.js

@@ -24,11 +24,6 @@ export default function(opts) {
       const callExpr = buildElementCall(path.get("openingElement"), file);
 
       callExpr.arguments = callExpr.arguments.concat(path.node.children);
-
-      if (callExpr.arguments.length >= 3) {
-        callExpr._prettyCall = true;
-      }
-
       path.replaceWith(t.inherits(callExpr, path.node));
     },
   };

packages/babel-helper-function-name/src/index.js

@@ -64,7 +64,6 @@ function wrap(state, method, id, scope) {
         FUNCTION_ID: id,
         FUNCTION_KEY: scope.generateUidIdentifier(id.name),
       }).expression;
-      template.callee._skipModulesRemap = true;
 
       // shim in dummy params to retain function arity, if you try to read the
       // source then you'll get the original since it's proxied so it's all good

packages/babel-helper-replace-supers/src/index.js

@@ -4,7 +4,7 @@ import * as messages from "babel-messages";
 import * as t from "babel-types";
 
 // ✌️
-const HARDCORE_THIS_REF = Symbol();
+const HARDCORE_THIS_REF = new WeakSet();
 
 function isIllegalBareSuper(node, parent) {
   if (!t.isSuper(node)) return false;
@@ -57,7 +57,7 @@ const visitor = {
   },
 
   ThisExpression(path, state) {
-    if (!path.node[HARDCORE_THIS_REF]) {
+    if (!HARDCORE_THIS_REF.has(path.node)) {
       state.thises.push(path);
     }
   },
@@ -309,7 +309,7 @@ export default class ReplaceSupers {
 
   optimiseCall(callee, args) {
     const thisNode = t.thisExpression();
-    thisNode[HARDCORE_THIS_REF] = true;
+    HARDCORE_THIS_REF.add(thisNode);
     return optimiseCall(callee, thisNode, args);
   }
 }

packages/babel-plugin-transform-es2015-block-scoping/src/index.js

@@ -8,6 +8,8 @@ import values from "lodash/values";
 import extend from "lodash/extend";
 import template from "babel-template";
 
+const DONE = new WeakSet();
+
 export default function() {
   return {
     visitor: {
@@ -340,8 +342,8 @@ class BlockScoping {
 
   run() {
     const block = this.block;
-    if (block._letDone) return;
+    if (DONE.has(block)) return;
-    block._letDone = true;
+    DONE.add(block);
 
     const needsClosure = this.getLetReferences();
 

packages/babel-plugin-transform-es2015-classes/src/vanilla.js

@@ -565,7 +565,6 @@ export default class ClassTransformer {
 
     t.inheritsComments(construct, method);
 
-    construct._ignoreUserWhitespace = true;
     construct.params = method.params;
 
     t.inherits(construct.body, method.body);

packages/babel-plugin-transform-es2015-classes/test/fixtures/regression/2775/expected.js

@@ -20,17 +20,9 @@ var RandomComponent = function (_Component) {
   babelHelpers.createClass(RandomComponent, [{
     key: "render",
     value: function render() {
-      return _react2.default.createElement(
+      return _react2.default.createElement("div", {
-        "div",
+        className: "sui-RandomComponent"
-        {
+      }, _react2.default.createElement("h2", null, "Hi there!"));
-          className: "sui-RandomComponent"
-        },
-        _react2.default.createElement(
-          "h2",
-          null,
-          "Hi there!"
-        )
-      );
     }
   }]);
   return RandomComponent;

packages/babel-plugin-transform-jscript/src/index.js

@@ -5,7 +5,6 @@ export default function({ types: t }) {
         exit(path) {
           const { node } = path;
           if (!node.id) return;
-          node._ignoreUserWhitespace = true;
 
           path.replaceWith(
             t.callExpression(

packages/babel-plugin-transform-react-constant-elements/src/index.js

@@ -1,4 +1,6 @@
 export default function({ types: t }) {
+  const HOISTED = new WeakSet();
+
   const immutabilityVisitor = {
     enter(path, state) {
       const stop = () => {
@@ -59,15 +61,14 @@ export default function({ types: t }) {
   return {
     visitor: {
       JSXElement(path) {
-        if (path.node._hoisted) return;
+        if (HOISTED.has(path.node)) return;
+        HOISTED.add(path.node);
 
         const state = { isImmutable: true };
         path.traverse(immutabilityVisitor, state);
 
         if (state.isImmutable) {
           path.hoist();
-        } else {
-          path.node._hoisted = true;
         }
       },
     },

packages/babel-plugin-transform-react-jsx/test/fixtures/react/arrow-functions/expected.js

@@ -12,4 +12,4 @@ var bar = function () {
   return function () {
     return React.createElement(_this2.foo, null);
   };
-};
+};

packages/babel-plugin-transform-react-jsx/test/fixtures/react/concatenates-adjacent-string-literals/expected.js

@@ -1,15 +1 @@
-var x = React.createElement(
+var x = React.createElement("div", null, "foo", "bar", "baz", React.createElement("div", null, "buz bang"), "qux", null, "quack");
-  "div",
-  null,
-  "foo",
-  "bar",
-  "baz",
-  React.createElement(
-    "div",
-    null,
-    "buz bang"
-  ),
-  "qux",
-  null,
-  "quack"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/dont-coerce-expression-containers/expected.js

@@ -1,7 +1 @@
-React.createElement(
+React.createElement(Text, null, "To get started, edit index.ios.js!!!", "\n", "Press Cmd+R to reload");
-  Text,
-  null,
-  "To get started, edit index.ios.js!!!",
-  "\n",
-  "Press Cmd+R to reload"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/honor-custom-jsx-comment-if-jsx-pragma-option-set/expected.js

@@ -1,15 +1,6 @@
 /** @jsx dom */
 dom(Foo, null);
-var profile = dom(
+var profile = dom("div", null, dom("img", {
-  "div",
+  src: "avatar.png",
-  null,
+  className: "profile"
-  dom("img", {
+}), dom("h3", null, [user.firstName, user.lastName].join(" ")));
-    src: "avatar.png",
-    className: "profile"
-  }),
-  dom(
-    "h3",
-    null,
-    [user.firstName, user.lastName].join(" ")
-  )
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/honor-custom-jsx-comment/expected.js

@@ -1,15 +1,6 @@
 /** @jsx dom */
 dom(Foo, null);
-var profile = dom(
+var profile = dom("div", null, dom("img", {
-  "div",
+  src: "avatar.png",
-  null,
+  className: "profile"
-  dom("img", {
+}), dom("h3", null, [user.firstName, user.lastName].join(" ")));
-    src: "avatar.png",
-    className: "profile"
-  }),
-  dom(
-    "h3",
-    null,
-    [user.firstName, user.lastName].join(" ")
-  )
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/honor-custom-jsx-pragma-option/expected.js

@@ -1,14 +1,5 @@
 dom(Foo, null);
-var profile = dom(
+var profile = dom("div", null, dom("img", {
-  "div",
+  src: "avatar.png",
-  null,
+  className: "profile"
-  dom("img", {
+}), dom("h3", null, [user.firstName, user.lastName].join(" ")));
-    src: "avatar.png",
-    className: "profile"
-  }),
-  dom(
-    "h3",
-    null,
-    [user.firstName, user.lastName].join(" ")
-  )
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/jsx-with-retainlines-option/expected.js

@@ -1 +1 @@
-var div = React.createElement("div", null, "test");
+var div = React.createElement("div", null, "test");

packages/babel-plugin-transform-react-jsx/test/fixtures/react/jsx-without-retainlines-option/expected.js

@@ -1,5 +1 @@
-var div = React.createElement(
+var div = React.createElement("div", null, "test");
-  "div",
-  null,
-  "test"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-allow-deeper-js-namespacing/expected.js

@@ -1 +1 @@
-React.createElement(Namespace.DeepNamespace.Component, null);
+React.createElement(Namespace.DeepNamespace.Component, null);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-allow-js-namespacing/expected.js

@@ -1 +1 @@
-React.createElement(Namespace.Component, null);
+React.createElement(Namespace.Component, null);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-avoid-wrapping-in-extra-parens-if-not-needed/expected.js

@@ -1,20 +1,4 @@
-var x = React.createElement(
+var x = React.createElement("div", null, React.createElement(Component, null));
-  "div",
+var x = React.createElement("div", null, props.children);
-  null,
+var x = React.createElement(Composite, null, props.children);
-  React.createElement(Component, null)
+var x = React.createElement(Composite, null, React.createElement(Composite2, null));
-);
-var x = React.createElement(
-  "div",
-  null,
-  props.children
-);
-var x = React.createElement(
-  Composite,
-  null,
-  props.children
-);
-var x = React.createElement(
-  Composite,
-  null,
-  React.createElement(Composite2, null)
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-convert-simple-tags/expected.js

@@ -1 +1 @@
-var x = React.createElement("div", null);
+var x = React.createElement("div", null);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-convert-simple-text/expected.js

@@ -1,5 +1 @@
-var x = React.createElement(
+var x = React.createElement("div", null, "text");
-  "div",
-  null,
-  "text"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-escape-xhtml-jsxtext/expected.js

@@ -1,46 +1,9 @@
-React.createElement(
+React.createElement("div", null, "wow");
-  "div",
+React.createElement("div", null, "w\xF4w");
-  null,
+React.createElement("div", null, "w & w");
-  "wow"
+React.createElement("div", null, "w & w");
-);
+React.createElement("div", null, "w \xA0 w");
-React.createElement(
+React.createElement("div", null, "this should not parse as unicode: \\u00a0");
-  "div",
+React.createElement("div", null, "this should parse as nbsp: \xA0 ");
-  null,
+React.createElement("div", null, "this should parse as unicode: ", '\u00a0 ');
-  "w\xF4w"
+React.createElement("div", null, "w < w");
-);
-React.createElement(
-  "div",
-  null,
-  "w & w"
-);
-React.createElement(
-  "div",
-  null,
-  "w & w"
-);
-React.createElement(
-  "div",
-  null,
-  "w \xA0 w"
-);
-React.createElement(
-  "div",
-  null,
-  "this should not parse as unicode: \\u00a0"
-);
-React.createElement(
-  "div",
-  null,
-  "this should parse as nbsp: \xA0 "
-);
-React.createElement(
-  "div",
-  null,
-  "this should parse as unicode: ",
-  '\u00a0 '
-);
-React.createElement(
-  "div",
-  null,
-  "w < w"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-handle-attributed-elements/expected.js

@@ -1,18 +1,9 @@
 var HelloMessage = React.createClass({
   displayName: "HelloMessage",
   render: function () {
-    return React.createElement(
+    return React.createElement("div", null, "Hello ", this.props.name);
-      "div",
-      null,
-      "Hello ",
-      this.props.name
-    );
   }
 });
 React.render(React.createElement(HelloMessage, {
-  name: React.createElement(
+  name: React.createElement("span", null, "Sebastian")
-    "span",
-    null,
-    "Sebastian"
-  )
 }), mountNode);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-handle-has-own-property-correctly/expected.js

@@ -1,5 +1 @@
-React.createElement(
+React.createElement("hasOwnProperty", null, "testing");
-  "hasOwnProperty",
-  null,
-  "testing"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-have-correct-comma-in-nested-children/expected.js

@@ -1,17 +1 @@
-var x = React.createElement(
+var x = React.createElement("div", null, React.createElement("div", null, React.createElement("br", null)), React.createElement(Component, null, foo, React.createElement("br", null), bar), React.createElement("br", null));
-  "div",
-  null,
-  React.createElement(
-    "div",
-    null,
-    React.createElement("br", null)
-  ),
-  React.createElement(
-    Component,
-    null,
-    foo,
-    React.createElement("br", null),
-    bar
-  ),
-  React.createElement("br", null)
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-not-mangle-expressioncontainer-attribute-values/expected.js

@@ -1,7 +1,3 @@
-React.createElement(
+React.createElement("button", {
-  "button",
+  "data-value": "a value\n  with\nnewlines\n   and spaces"
-  {
+}, "Button");
-    "data-value": "a value\n  with\nnewlines\n   and spaces"
-  },
-  "Button"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-quote-jsx-attributes/expected.js

@@ -1,7 +1,3 @@
-React.createElement(
+React.createElement("button", {
-  "button",
+  "data-value": "a value"
-  {
+}, "Button");
-    "data-value": "a value"
-  },
-  "Button"
-);

packages/babel-plugin-transform-react-jsx/test/fixtures/react/should-transform-known-hyphenated-tags/expected.js

@@ -1 +1 @@
-React.createElement("font-face", null);
+React.createElement("font-face", null);

packages/babel-template/src/index.js

@@ -2,10 +2,8 @@ import cloneDeep from "lodash/cloneDeep";
 import has from "lodash/has";
 import traverse from "babel-traverse";
 import * as babylon from "babylon";
-import * as t from "babel-types";
 
-const FROM_TEMPLATE = "_fromTemplate"; //Symbol(); // todo: probably wont get copied over
+const FROM_TEMPLATE = new Set();
-const TEMPLATE_SKIP = Symbol();
 
 export default function(code: string, opts?: Object): Function {
   // since we lazy parse the template, we get the current stack so we have the
@@ -40,10 +38,6 @@ export default function(code: string, opts?: Object): Function {
       ast = traverse.removeProperties(ast, {
         preserveComments: opts.preserveComments,
       });
-
-      traverse.cheap(ast, function(node) {
-        node[FROM_TEMPLATE] = true;
-      });
     } catch (err) {
       err.stack = `${err.stack}from\n${stack}`;
       throw err;
@@ -66,7 +60,13 @@ function useTemplate(ast, nodes?: Array<Object>) {
   const { program } = ast;
 
   if (nodes.length) {
+    traverse.cheap(ast, function(node) {
+      FROM_TEMPLATE.add(node);
+    });
+
     traverse(ast, templateVisitor, null, nodes);
+
+    FROM_TEMPLATE.clear();
   }
 
   if (program.body.length > 1) {
@@ -80,32 +80,27 @@ const templateVisitor = {
   // 360
   noScope: true,
 
-  enter(path, args) {
+  Identifier(path, args) {
-    let { node } = path;
+    const { node, parentPath } = path;
-    if (node[TEMPLATE_SKIP]) return path.skip();
+    if (!FROM_TEMPLATE.has(node)) return path.skip();
-
-    if (t.isExpressionStatement(node)) {
-      node = node.expression;
-    }
 
     let replacement;
+    if (has(args[0], node.name)) {
+      replacement = args[0][node.name];
+    } else if (node.name[0] === "$") {
+      const i = +node.name.slice(1);
+      if (args[i]) replacement = args[i];
+    }
 
-    if (t.isIdentifier(node) && node[FROM_TEMPLATE]) {
+    if (parentPath.isExpressionStatement()) {
-      if (has(args[0], node.name)) {
+      path = parentPath;
-        replacement = args[0][node.name];
-      } else if (node.name[0] === "$") {
-        const i = +node.name.slice(1);
-        if (args[i]) replacement = args[i];
-      }
     }
 
     if (replacement === null) {
       path.remove();
-    }
+    } else if (replacement) {
-
-    if (replacement) {
-      replacement[TEMPLATE_SKIP] = true;
       path.replaceInline(replacement);
+      path.skip();
     }
   },
 

packages/babel-traverse/src/path/lib/hoister.js

@@ -199,10 +199,6 @@ export default class PathHoister {
   }
 
   run() {
-    const node = this.path.node;
-    if (node._hoisted) return;
-    node._hoisted = true;
-
     this.path.traverse(referenceVisitor, this);
 
     this.getCompatibleScopes();

packages/babel-traverse/src/scope/index.js

@@ -803,7 +803,6 @@ export default class Scope {
 
     if (!declarPath) {
       const declar = t.variableDeclaration(kind, []);
-      declar._generated = true;
       declar._blockHoist = blockHoist;
 
       [declarPath] = path.unshiftContainer("body", [declar]);

packages/babel-types/src/index.js

@@ -304,7 +304,7 @@ export function clone(node: Object): Object {
 
 export function cloneWithoutLoc(node: Object): Object {
   const newNode = clone(node);
-  delete newNode.loc;
+  newNode.loc = null;
   return newNode;
 }
 
@@ -405,7 +405,7 @@ export function buildMatchMemberExpression(
 
 export function removeComments(node: Object): Object {
   for (const key of t.COMMENT_KEYS) {
-    delete node[key];
+    node[key] = null;
   }
   return node;
 }
@@ -455,7 +455,7 @@ export function inherits(child: Object, parent: Object): Object {
 
   // force inherit "private" properties
   for (const key in parent) {
-    if (key[0] === "_") child[key] = parent[key];
+    if (key[0] === "_" && key !== "__clone") child[key] = parent[key];
   }
 
   // force inherit select properties