fix(transformers): fix matching indices for word-highlight (#909)

* fix(transformerMetaWordHighlight): use regex instead of substring to find matching indices; add tests

* chore: fix

* chore: update

---------

Co-authored-by: Anthony Fu <[email protected]>

Author: artt

packages/transformers/src/transformers/meta-highlight-word.ts

@@ -55,11 +55,17 @@ export function transformerMetaWordHighlight(
   }
 }
 
-function findAllSubstringIndexes(str: string, substr: string): number[] {
-  const indexes = []
-  let i = -1
-  // eslint-disable-next-line no-cond-assign
-  while ((i = str.indexOf(substr, i + 1)) !== -1)
-    indexes.push(i)
+export function findAllSubstringIndexes(str: string, substr: string): number[] {
+  const indexes: number[] = []
+  let cursor = 0
+  while (true) {
+    const index = str.indexOf(substr, cursor)
+    if (index === -1 || index >= str.length)
+      break
+    if (index < cursor)
+      break
+    indexes.push(index)
+    cursor = index + substr.length
+  }
   return indexes
 }

packages/transformers/test/meta-word-highlight.test.ts

@@ -1,9 +1,11 @@
 import { expect, it } from 'vitest'
-import { parseMetaHighlightWords } from '../src/transformers/meta-highlight-word'
+import { findAllSubstringIndexes, parseMetaHighlightWords } from '../src/transformers/meta-highlight-word'
 
 it('parseHighlightWords', () => {
   expect(parseMetaHighlightWords('')).toEqual([])
   expect(parseMetaHighlightWords('/hello/')).toEqual(['hello'])
   expect(parseMetaHighlightWords('/ /f /hello/')).toEqual([' ', 'hello'])
   expect(parseMetaHighlightWords('/foo bar/ /foo.bar\\/foo/')).toEqual(['foo bar', 'foo.bar/foo'])
+  expect(findAllSubstringIndexes('xxx', 'xx')).toEqual([0])
+  expect(findAllSubstringIndexes('xxxx', 'xx')).toEqual([0, 2])
 })