Typecheck formatter_worker/AcornTokenizer.js with TypeScript

The `.mjs.d.ts` file has been upstreamed in
acornjs/acorn#954 as per the instructions in
microsoft/TypeScript#27957 (comment)

R=jacktfranklin@chromium.org,bmeurer@chromium.org

Bug: 1011811
Change-Id: Ia2e0c3145318ac93b5e49d2b40780ffe7c469bab
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2218015
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
Reviewed-by: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>

front_end/formatter_worker/AcornTokenizer.js

@@ -2,13 +2,16 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @ts-nocheck
-// TODO(crbug.com/1011811): Enable TypeScript compiler checks
-
 import * as Platform from '../platform/platform.js';
 import * as TextUtils from '../text_utils/text_utils.js';
 import * as Acorn from '../third_party/acorn/package/dist/acorn.mjs';
 
+/**
+ * @typedef {(!Acorn.Token|!Acorn.Comment)}
+ */
+// @ts-ignore typedef
+export let TokenOrComment;
+
 /**
  * @unrestricted
  */
@@ -18,17 +21,19 @@ export class AcornTokenizer {
    */
   constructor(content) {
     this._content = content;
+    /** @type {!Array<!Acorn.Comment>} */
     this._comments = [];
     this._tokenizer = Acorn.tokenizer(this._content, {onComment: this._comments, ecmaVersion: ECMA_VERSION});
     const contentLineEndings = Platform.StringUtilities.findLineEndingIndexes(this._content);
     this._textCursor = new TextUtils.TextCursor.TextCursor(contentLineEndings);
     this._tokenLineStart = 0;
     this._tokenLineEnd = 0;
+    this._tokenColumnStart = 0;
     this._nextTokenInternal();
   }
 
   /**
-   * @param {!Acorn.Acorn.TokenOrComment} token
+   * @param {!Acorn.Token} token
    * @param {string=} values
    * @return {boolean}
    */
@@ -39,7 +44,7 @@ export class AcornTokenizer {
   }
 
   /**
-   * @param {!Acorn.Acorn.TokenOrComment} token
+   * @param {!Acorn.Token} token
    * @param {string=} keyword
    * @return {boolean}
    */
@@ -49,7 +54,7 @@ export class AcornTokenizer {
   }
 
   /**
-   * @param {!Acorn.Acorn.TokenOrComment} token
+   * @param {!TokenOrComment} token
    * @param {string=} identifier
    * @return {boolean}
    */
@@ -58,36 +63,36 @@ export class AcornTokenizer {
   }
 
   /**
-   * @param {!Acorn.Acorn.TokenOrComment} token
+   * @param {!TokenOrComment} token
    * @return {boolean}
    */
   static lineComment(token) {
     return token.type === 'Line';
   }
 
   /**
-   * @param {!Acorn.Acorn.TokenOrComment} token
+   * @param {!TokenOrComment} token
    * @return {boolean}
    */
   static blockComment(token) {
     return token.type === 'Block';
   }
 
   /**
-   * @return {!Acorn.Acorn.TokenOrComment}
+   * @return {!TokenOrComment}
    */
   _nextTokenInternal() {
     if (this._comments.length) {
-      return this._comments.shift();
+      return /** @type {!TokenOrComment} */ (this._comments.shift());
     }
     const token = this._bufferedToken;
 
     this._bufferedToken = this._tokenizer.getToken();
-    return token;
+    return /** @type {!TokenOrComment} */ (token);
   }
 
   /**
-   * @return {?Acorn.Acorn.TokenOrComment}
+   * @return {?TokenOrComment}
    */
   nextToken() {
     const token = this._nextTokenInternal();
@@ -105,12 +110,15 @@ export class AcornTokenizer {
   }
 
   /**
-   * @return {?Acorn.Acorn.TokenOrComment}
+   * @return {?TokenOrComment}
    */
   peekToken() {
     if (this._comments.length) {
       return this._comments[0];
     }
+    if (!this._bufferedToken) {
+      return null;
+    }
     return this._bufferedToken.type !== Acorn.tokTypes.eof ? this._bufferedToken : null;
   }
 

front_end/formatter_worker/JavaScriptFormatter.js

@@ -33,7 +33,7 @@
 
 import * as Acorn from '../third_party/acorn/package/dist/acorn.mjs';
 
-import {AcornTokenizer, ECMA_VERSION} from './AcornTokenizer.js';
+import {AcornTokenizer, ECMA_VERSION, TokenOrComment} from './AcornTokenizer.js';  // eslint-disable-line no-unused-vars
 import {ESTreeWalker} from './ESTreeWalker.js';
 import {FormattedContentBuilder} from './FormattedContentBuilder.js';  // eslint-disable-line no-unused-vars
 
@@ -67,7 +67,7 @@ export class JavaScriptFormatter {
   }
 
   /**
-   * @param {?Acorn.Acorn.TokenOrComment} token
+   * @param {?TokenOrComment} token
    * @param {string} format
    */
   _push(token, format) {
@@ -100,7 +100,7 @@ export class JavaScriptFormatter {
       return;
     }
     while (this._tokenizer.peekToken() && this._tokenizer.peekToken().start < node.start) {
-      const token = /** @type {!Acorn.Acorn.TokenOrComment} */ (this._tokenizer.nextToken());
+      const token = /** @type {!TokenOrComment} */ (this._tokenizer.nextToken());
       const format = this._formatToken(node.parent, token);
       this._push(token, format);
     }
@@ -111,7 +111,7 @@ export class JavaScriptFormatter {
    */
   _afterVisit(node) {
     while (this._tokenizer.peekToken() && this._tokenizer.peekToken().start < node.end) {
-      const token = /** @type {!Acorn.Acorn.TokenOrComment} */ (this._tokenizer.nextToken());
+      const token = /** @type {!TokenOrComment} */ (this._tokenizer.nextToken());
       const format = this._formatToken(node, token);
       this._push(token, format);
     }
@@ -138,17 +138,18 @@ export class JavaScriptFormatter {
 
   /**
    * @param {!ESTree.Node} node
-   * @param {!Acorn.Acorn.TokenOrComment} token
+   * @param {!TokenOrComment} tokenOrComment
    * @return {string}
    */
-  _formatToken(node, token) {
+  _formatToken(node, tokenOrComment) {
     const AT = AcornTokenizer;
-    if (AT.lineComment(token)) {
+    if (AT.lineComment(tokenOrComment)) {
       return 'tn';
     }
-    if (AT.blockComment(token)) {
+    if (AT.blockComment(tokenOrComment)) {
       return 'tn';
     }
+    const token = /** @type {!Acorn.Token} */ (tokenOrComment);
     if (node.type === 'ContinueStatement' || node.type === 'BreakStatement') {
       return node.label && AT.keyword(token) ? 'ts' : 't';
     }

front_end/third_party/acorn/BUILD.gn

@@ -8,6 +8,7 @@ copy("acorn") {
     "package/dist/acorn.d.ts",
     "package/dist/acorn.js",
     "package/dist/acorn.mjs",
+    "package/dist/acorn.mjs.d.ts",
     "package/dist/acorn.mjs.map",
   ]
 

front_end/third_party/acorn/package/dist/acorn.mjs.d.ts

@@ -0,0 +1,2 @@
+import * as acorn from "./acorn";
+export = acorn;

front_end/third_party/acorn/package/dist/acorn_types.mjs

@@ -3,7 +3,7 @@ export const Acorn = {};
  * @constructor
  */
 Acorn.Tokenizer = function() {
-  /** @type {function():!Acorn.Token} */
+  /** @type {function():!Token} */
   this.getToken;
 };
 
@@ -20,17 +20,12 @@ Acorn.TokenType = function() {
 /**
  * @typedef {{type: !Acorn.TokenType, value: string, start: number, end: number}}
  */
-Acorn.Token;
+export let Token;
 
 /**
  * @typedef {{type: string, value: string, start: number, end: number}}
  */
-Acorn.Comment;
-
-/**
- * @typedef {(!Acorn.Token|!Acorn.Comment)}
- */
-Acorn.TokenOrComment;
+export let Comment;
 
 /**
  * @param {string} text