{
  "id": 13901586,
  "title": "你在错误的进行字符遍历",
  "url": "https://urgent.news/2026/10/12/story-13901586",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-10-12T07:40:02.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/freecoderx/ni-zai-cuo-wu-de-jin-xing-zi-fu-bian-li-2m0f"
  },
  "original_language": "en",
  "account": "The provided code has an issue with the way it handles Unicode characters when traversing them using the `charCodeAt` method. The problem arises because the `charCodeAt` method reads characters one byte at a time, which can lead to incorrect interpretation of multi-byte Unicode characters. This results in breaking down a three-byte character into two separate characters, leading to incorrect character representation.\n\nWhen the `pickUnicodeFor` function is called with the Unicode character \"𤮮\", it outputs an array with the Unicode escape sequences for the two separate bytes that make up the character. The output is `[\"\\uD850\", \"\\uDEEE\"]`, which is incorrect because the original character \"𤮮\" should be represented as a single Unicode escape sequence `\"\\u{242EE}\"`.\n\nTo resolve this issue, the author suggests using the `for...of` loop instead of `charCodeAt` for character traversal. The `for...of` loop automatically iterates over characters, correctly handling multi-byte Unicode characters by treating them as a single unit rather than breaking them down into individual bytes. The code snippet provided for `pickUnicodeForOf` demonstrates the correct way to traverse Unicode characters using `for...of`. By applying this method, the function accurately outputs the correct Unicode escape sequence for the character \"𤮮\" as `[\"\\u{242EE}\"]`.\n\nIn summary, the mistake in the original code lies in the improper handling of Unicode characters when using `charCodeAt`. The corrected approach is to utilize the `for...of` loop, which provides a reliable way to iterate over characters while preserving their integrity, even when dealing with multi-byte Unicode characters.",
  "summary": "有问题相关代码 function pickUnicodeFor ( value ) { let unicodeSet = new Set (); let strLen = value . length ; for ( let i = 0 ; i < strLen ; i ++ ) { let word = value . charCodeAt ( i ); if ( word && ! unicodeSet . has ( word )) { word = ` \\\\ u ${ word . toString ( 16 ). toUpperCase ()} ` ; unicodeSet . add ( word ); } } return Array . from ( unicodeSet ); } const unicodeList = pickUnicodeFor ( \" 𤋮 \"…",
  "key_points": [
    "Code mishandles Unicode characters with charCodeAt method",
    "pickUnicodeFor outputs incorrect byte representation of 𤮮",
    "for...of loop correctly traverses multi-byte Unicode characters"
  ],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}