[7.0] Change for-await to use new AST (#5321)

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

@@ -84,10 +84,9 @@ const buildForXStatement = function (op) {
   return function (node: Object) {
     this.word("for");
     this.space();
-    if (op === "await") {
+    if (op === "of" && node.await) {
       this.word("await");
       this.space();
-      op = "of";
     }
     this.token("(");
 
@@ -103,7 +102,6 @@ const buildForXStatement = function (op) {
 
 export const ForInStatement = buildForXStatement("in");
 export const ForOfStatement = buildForXStatement("of");
-export const ForAwaitStatement = buildForXStatement("await");
 
 export function DoWhileStatement(node: Object) {
   this.word("do");

packages/babel-helper-remap-async-to-generator/src/index.js

@@ -41,8 +41,9 @@ const awaitVisitor = {
     }
   },
 
-  ForAwaitStatement(path, { file, wrapAwait }) {
+  ForOfStatement(path, { file, wrapAwait }) {
     const { node } = path;
+    if (!node.await) return;
 
     const build = rewriteForAwait(path, {
       getAsyncIterator: file.addHelper("asyncIterator"),

packages/babel-plugin-transform-object-rest-spread/test/fixtures/object-rest/for-x/expected.js

@@ -18,11 +18,11 @@ async function a() {
 for ({ a } in {}) {}
 for ({ a } of []) {}
 async function a() {
-  for ({ a } of []) {}
+  for await ({ a } of []) {}
 }
 
 for (a in {}) {}
 for (a of []) {}
 async function a() {
-  for (a of []) {}
+  for await (a of []) {}
 }

packages/babel-types/README.md

@@ -694,21 +694,6 @@ See also `t.isFile(node, opts)` and `t.assertFile(node, opts)`.
 
 ---
 
-### forAwaitStatement
-```javascript
-t.forAwaitStatement(left, right, body)
-```
-
-See also `t.isForAwaitStatement(node, opts)` and `t.assertForAwaitStatement(node, opts)`.
-
-Aliases: `Scopable`, `Statement`, `For`, `BlockParent`, `Loop`, `ForXStatement`
-
- - `left`: `VariableDeclaration | LVal` (required)
- - `right`: `Expression` (required)
- - `body`: `Statement` (required)
-
----
-
 ### forInStatement
 ```javascript
 t.forInStatement(left, right, body)
@@ -726,7 +711,7 @@ Aliases: `Scopable`, `Statement`, `For`, `BlockParent`, `Loop`, `ForXStatement`
 
 ### forOfStatement
 ```javascript
-t.forOfStatement(left, right, body)
+t.forOfStatement(left, right, body, await)
 ```
 
 See also `t.isForOfStatement(node, opts)` and `t.assertForOfStatement(node, opts)`.
@@ -736,6 +721,7 @@ Aliases: `Scopable`, `Statement`, `For`, `BlockParent`, `Loop`, `ForXStatement`
  - `left`: `VariableDeclaration | LVal` (required)
  - `right`: `Expression` (required)
  - `body`: `Statement` (required)
+ - `await`: `boolean` (default: `false`)
 
 ---
 

packages/babel-types/src/definitions/es2015.js

@@ -178,6 +178,10 @@ defineType("ForOfStatement", {
     },
     body: {
       validate: assertNodeType("Statement")
+    },
+    await: {
+      default: false,
+      validate: assertValueType("boolean")
     }
   }
 });

packages/babel-types/src/definitions/experimental.js

@@ -11,22 +11,6 @@ defineType("AwaitExpression", {
   }
 });
 
-defineType("ForAwaitStatement", {
-  visitor: ["left", "right", "body"],
-  aliases: ["Scopable", "Statement", "For", "BlockParent", "Loop", "ForXStatement"],
-  fields: {
-    left: {
-      validate: assertNodeType("VariableDeclaration", "LVal")
-    },
-    right: {
-      validate: assertNodeType("Expression")
-    },
-    body: {
-      validate: assertNodeType("Statement")
-    }
-  }
-});
-
 defineType("BindExpression", {
   visitor: ["object", "callee"],
   aliases: ["Expression"],