fix(typescript-estree): improve comment parsing code

packages/typescript-estree/package.json

@@ -43,7 +43,8 @@
     "glob": "^7.1.4",
     "is-glob": "^4.0.1",
     "lodash.unescape": "4.0.1",
-    "semver": "^6.3.0"
+    "semver": "^6.3.0",
+    "tsutils": "^3.17.1"
   },
   "devDependencies": {
     "@babel/code-frame": "7.5.5",

packages/typescript-estree/src/convert-comments.ts

@@ -1,82 +1,8 @@
 import * as ts from 'typescript'; // leave this as * as ts so people using util package don't need syntheticDefaultImports
-import { getLocFor, getNodeContainer } from './node-utils';
+import { forEachComment } from 'tsutils';
+import { getLocFor } from './node-utils';
 import { TSESTree } from './ts-estree';
 
-/**
- * Converts a TypeScript comment to an Esprima comment.
- * @param block True if it's a block comment, false if not.
- * @param text The text of the comment.
- * @param start The index at which the comment starts.
- * @param end The index at which the comment ends.
- * @param startLoc The location at which the comment starts.
- * @param endLoc The location at which the comment ends.
- * @returns The comment object.
- * @internal
- */
-function convertTypeScriptCommentToEsprimaComment(
-  block: boolean,
-  text: string,
-  start: number,
-  end: number,
-  startLoc: TSESTree.LineAndColumnData,
-  endLoc: TSESTree.LineAndColumnData,
-): TSESTree.Comment {
-  const comment: TSESTree.OptionalRangeAndLoc<TSESTree.Comment> = {
-    type: block ? 'Block' : 'Line',
-    value: text,
-  };
-
-  if (typeof start === 'number') {
-    comment.range = [start, end];
-  }
-
-  if (typeof startLoc === 'object') {
-    comment.loc = {
-      start: startLoc,
-      end: endLoc,
-    };
-  }
-
-  return comment as TSESTree.Comment;
-}
-
-/**
- * Convert comment from TypeScript Triva Scanner.
- * @param triviaScanner TS Scanner
- * @param ast the AST object
- * @param code TypeScript code
- * @returns the converted Comment
- * @private
- */
-function getCommentFromTriviaScanner(
-  triviaScanner: ts.Scanner,
-  ast: ts.SourceFile,
-  code: string,
-): TSESTree.Comment {
-  const kind = triviaScanner.getToken();
-  const isBlock = kind === ts.SyntaxKind.MultiLineCommentTrivia;
-  const range = {
-    pos: triviaScanner.getTokenPos(),
-    end: triviaScanner.getTextPos(),
-    kind: triviaScanner.getToken(),
-  };
-
-  const comment = code.substring(range.pos, range.end);
-  const text = isBlock
-    ? comment.replace(/^\/\*/, '').replace(/\*\/$/, '')
-    : comment.replace(/^\/\//, '');
-  const loc = getLocFor(range.pos, range.end, ast);
-
-  return convertTypeScriptCommentToEsprimaComment(
-    isBlock,
-    text,
-    range.pos,
-    range.end,
-    loc.start,
-    loc.end,
-  );
-}
-
 /**
  * Convert all comments for the given AST.
  * @param ast the AST object
@@ -90,93 +16,33 @@ export function convertComments(
 ): TSESTree.Comment[] {
   const comments: TSESTree.Comment[] = [];
 
-  /**
-   * Create a TypeScript Scanner, with skipTrivia set to false so that
-   * we can parse the comments
-   */
-  const triviaScanner = ts.createScanner(
-    ast.languageVersion,
-    false,
-    ast.languageVariant,
-    code,
+  forEachComment(
+    ast,
+    (_, comment) => {
+      const type =
+        comment.kind == ts.SyntaxKind.SingleLineCommentTrivia
+          ? 'Line'
+          : 'Block';
+      const range: TSESTree.Range = [comment.pos, comment.end];
+      const loc = getLocFor(range[0], range[1], ast);
+
+      // both comments start with 2 characters - /* or //
+      const textStart = range[0] + 2;
+      const textEnd =
+        comment.kind === ts.SyntaxKind.SingleLineCommentTrivia
+          ? // single line comments end at the end
+            range[1] - textStart
+          : // multiline comments end 2 characters early
+            range[1] - textStart - 2;
+      comments.push({
+        type,
+        value: code.substr(textStart, textEnd),
+        range,
+        loc,
+      });
+    },
+    ast,
   );
 
-  let kind = triviaScanner.scan();
-  while (kind !== ts.SyntaxKind.EndOfFileToken) {
-    const start = triviaScanner.getTokenPos();
-    const end = triviaScanner.getTextPos();
-
-    let container: ts.Node | null = null;
-    switch (kind) {
-      case ts.SyntaxKind.SingleLineCommentTrivia:
-      case ts.SyntaxKind.MultiLineCommentTrivia: {
-        const comment = getCommentFromTriviaScanner(triviaScanner, ast, code);
-
-        comments.push(comment);
-        break;
-      }
-      case ts.SyntaxKind.GreaterThanToken:
-        container = getNodeContainer(ast, start, end);
-        if (
-          (container.parent &&
-            container.parent.parent &&
-            // Rescan after an opening element or fragment
-            (container.parent.kind === ts.SyntaxKind.JsxOpeningElement &&
-              // Make sure this is the end of a tag like `<Component<number>>`
-              container.parent.end === end)) ||
-          container.parent.kind === ts.SyntaxKind.JsxOpeningFragment ||
-          // Rescan after a self-closing element if it's inside another JSX element
-          (container.parent.kind === ts.SyntaxKind.JsxSelfClosingElement &&
-            (container.parent.parent.kind === ts.SyntaxKind.JsxElement ||
-              container.parent.parent.kind === ts.SyntaxKind.JsxFragment)) ||
-          // Rescan after a closing element if it's inside another JSX element
-          ((container.parent.kind === ts.SyntaxKind.JsxClosingElement ||
-            container.parent.kind === ts.SyntaxKind.JsxClosingFragment) &&
-            container.parent.parent.parent &&
-            (container.parent.parent.parent.kind === ts.SyntaxKind.JsxElement ||
-              container.parent.parent.parent.kind ===
-                ts.SyntaxKind.JsxFragment))
-        ) {
-          kind = triviaScanner.reScanJsxToken();
-          continue;
-        }
-        break;
-      case ts.SyntaxKind.CloseBraceToken:
-        container = getNodeContainer(ast, start, end);
-
-        // Rescan after a JSX expression
-        if (
-          container.parent &&
-          container.parent.kind === ts.SyntaxKind.JsxExpression &&
-          container.parent.parent &&
-          container.parent.parent.kind === ts.SyntaxKind.JsxElement
-        ) {
-          kind = triviaScanner.reScanJsxToken();
-          continue;
-        }
-
-        if (
-          container.kind === ts.SyntaxKind.TemplateMiddle ||
-          container.kind === ts.SyntaxKind.TemplateTail
-        ) {
-          kind = triviaScanner.reScanTemplateToken();
-          continue;
-        }
-        break;
-      case ts.SyntaxKind.SlashToken:
-      case ts.SyntaxKind.SlashEqualsToken:
-        container = getNodeContainer(ast, start, end);
-
-        if (container.kind === ts.SyntaxKind.RegularExpressionLiteral) {
-          kind = triviaScanner.reScanSlashToken();
-          continue;
-        }
-        break;
-      default:
-        break;
-    }
-    kind = triviaScanner.scan();
-  }
-
   return comments;
 }

packages/typescript-estree/src/node-utils.ts

@@ -612,41 +612,6 @@ export function convertTokens(ast: ts.SourceFile): TSESTree.Token[] {
   return result;
 }
 
-/**
- * Get container token node between range
- * @param ast the AST object
- * @param start The index at which the comment starts.
- * @param end The index at which the comment ends.
- * @returns typescript container token
- * @private
- */
-export function getNodeContainer(
-  ast: ts.SourceFile,
-  start: number,
-  end: number,
-): ts.Node {
-  let container: ts.Node | null = null;
-
-  /**
-   * @param node the ts.Node
-   */
-  function walk(node: ts.Node): void {
-    const nodeStart = node.pos;
-    const nodeEnd = node.end;
-
-    if (start >= nodeStart && end <= nodeEnd) {
-      if (isToken(node)) {
-        container = node;
-      } else {
-        node.getChildren().forEach(walk);
-      }
-    }
-  }
-  walk(ast);
-
-  return container!;
-}
-
 export interface TSError {
   index: number;
   lineNumber: number;