{"id":6570,"date":"2026-08-12T16:11:11","date_gmt":"2026-08-12T07:11:11","guid":{"rendered":"https:\/\/route-zero.com\/recruit\/?post_type=route&p=6570"},"modified":"2026-11-12T16:11:18","modified_gmt":"2026-11-12T07:11:18","slug":"nodejs-refactor-regression-test-beginner","status":"publish","type":"route","link":"https:\/\/route-zero.com\/recruit\/route\/6570\/","title":{"rendered":"AI\u304c\u66f8\u304d\u63db\u3048\u305fJavaScript\u306e\u52d5\u4f5c\u3092\u5b88\u308b\u306b\u306f\uff1fNode.js\u6a19\u6e96\u30c6\u30b9\u30c8\u3067\u78ba\u8a8d\u3059\u308b\u65b9\u6cd5"},"content":{"rendered":"

AI\u306bJavaScript\u3092\u76f4\u3057\u3066\u3082\u3089\u3063\u305f\u5f8c\u3001\u300c\u898b\u305f\u76ee\u306f\u3059\u3063\u304d\u308a\u3057\u305f\u3051\u308c\u3069\u3001\u672c\u5f53\u306b\u524d\u3068\u540c\u3058\u52d5\u304d\u306a\u306e\u304b\u300d\u3068\u8ff7\u3046\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002\u305d\u3093\u306a\u3068\u304d\u306f\u3001\u4fee\u6b63\u524d\u306b\u5165\u529b\u3068\u671f\u5f85\u3059\u308b\u51fa\u529b\u3092\u30c6\u30b9\u30c8\u3068\u3057\u3066\u4fdd\u5b58<\/strong>\u3057\u3001\u4fee\u6b63\u5f8c\u306b\u540c\u3058\u30c6\u30b9\u30c8\u3092\u5b9f\u884c\u3057\u307e\u3059\u3002\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001\u67b6\u7a7a\u306e\u5b66\u7fd2\u8a18\u9332\u306e\u96c6\u8a08\u6a5f\u80fd\u3092\u4f7f\u3044\u3001\u8ffd\u52a0\u30e9\u30a4\u30d6\u30e9\u30ea\u306a\u3057\u3067\u78ba\u304b\u3081\u308b\u65b9\u6cd5\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n

\u300c\u8aad\u307f\u3084\u3059\u304f\u306a\u3063\u305f\u300d\u3068\u300c\u6b63\u3057\u304f\u52d5\u304f\u300d\u306f\u5225\u306e\u78ba\u8a8d<\/h2>\n

\u30ea\u30d5\u30a1\u30af\u30bf\u30ea\u30f3\u30b0\u3068\u306f\u3001\u5229\u7528\u8005\u304b\u3089\u898b\u3048\u308b\u52d5\u4f5c\u3092\u4fdd\u3061\u306a\u304c\u3089\u5185\u90e8\u306e\u30b3\u30fc\u30c9\u69cb\u9020\u3092\u898b\u76f4\u3059\u3053\u3068\u3067\u3059\u3002\u753b\u9762\u306e\u6a5f\u80fd\u8ffd\u52a0\u3084\u8a08\u7b97\u7d50\u679c\u306e\u5909\u66f4\u307e\u3067\u542b\u3081\u308b\u5834\u5408\u306f\u3001\u5358\u306a\u308b\u5185\u90e8\u6574\u7406\u3068\u306f\u533a\u5225\u3057\u307e\u3059\u3002<\/p>\n

\u3053\u3053\u3067\u78ba\u8a8d\u3059\u308b\u306e\u306f\u3001\u5b9f\u884c\u306b\u6210\u529f\u3057\u305f\u304b\u3060\u3051\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u300c\u5b8c\u4e86\u6e08\u307f\u306e\u5b66\u7fd2\u8a18\u9332\u3060\u3051\u3092\u96c6\u8a08\u3059\u308b\u300d\u3068\u3044\u3046\u6c7a\u3081\u3054\u3068\u304c\u3001\u66f8\u304d\u63db\u3048\u5f8c\u3082\u5b88\u3089\u308c\u3066\u3044\u308b\u304b\u3067\u3059\u3002\u30c6\u30b9\u30c8\u306f\u5165\u529b\u4f8b\u3054\u3068\u306b\u671f\u5f85\u7d50\u679c\u3092\u660e\u793a\u3067\u304d\u308b\u305f\u3081\u3001\u52d8\u3067\u306f\u306a\u304f\u6bd4\u8f03\u3067\u5224\u65ad\u3067\u304d\u307e\u3059\u3002<\/p>\n

\n

\u7528\u8a9e\u89e3\u8aac\uff1a\u56de\u5e30\u30c6\u30b9\u30c8<\/strong>
\u4fee\u6b63\u3067\u904e\u53bb\u306b\u52d5\u3044\u3066\u3044\u305f\u6a5f\u80fd\u304c\u58ca\u308c\u3066\u3044\u306a\u3044\u304b\u3092\u78ba\u304b\u3081\u308b\u30c6\u30b9\u30c8\u3002\u3059\u3079\u3066\u306e\u4e0d\u5177\u5408\u3092\u898b\u3064\u3051\u3089\u308c\u308b\u4fdd\u8a3c\u3067\u306f\u306a\u304f\u3001\u7528\u610f\u3057\u305f\u6761\u4ef6\u306e\u7bc4\u56f2\u3067\u7570\u5e38\u3092\u691c\u77e5\u3057\u307e\u3059\u3002<\/p>\n<\/blockquote>\n

\uff08\u30ea\u30d5\u30a1\u30af\u30bf\u30ea\u30f3\u30b0\u306e\u610f\u5473\u306b\u3064\u3044\u3066\u306f\u300eMartin Fowler\u306b\u3088\u308bRefactoring\u306e\u89e3\u8aac<\/a>\u300f\u3092\u3054\u53c2\u7167\u304f\u3060\u3055\u3044\uff09<\/p>\n

\u7df4\u7fd2\u3059\u308b\u6a5f\u80fd\u3068\u3001\u5909\u3048\u3066\u306f\u3044\u3051\u306a\u3044\u7d04\u675f<\/h2>\n

\u67b6\u7a7a\u306e\u5b66\u7fd2\u30e1\u30e2\u3092\u8003\u3048\u307e\u3059\u30021\u4ef6\u306e\u30c7\u30fc\u30bf\u306b\u306f\u300c\u5b66\u7fd2\u6642\u9593\u300d\u3068\u300c\u5b8c\u4e86\u3057\u305f\u304b\u3069\u3046\u304b\u300d\u304c\u5165\u3063\u3066\u3044\u307e\u3059\u3002`done`\u304c\u771f\u507d\u5024\u306e`true`\u306b\u306a\u3063\u3066\u3044\u308b\u8a18\u9332\u3060\u3051\u3092\u6570\u3048\u3001\u305d\u306e\u6642\u9593\u3092\u5408\u8a08\u3057\u307e\u3059\u3002\u3053\u3053\u3067\u306f`minutes`\u304c0\u4ee5\u4e0a\u306e\u6570\u5024\u3067\u6e21\u3055\u308c\u308b\u3053\u3068\u3092\u524d\u63d0\u306b\u3057\u307e\u3059\u3002<\/p>\n\n\n\n\n\n\n\n\n\n
\u5165\u529b\u306e\u72b6\u614b<\/th>\n\u6570\u3048\u308b\u4ef6\u6570<\/th>\n\u5408\u8a08\u6642\u9593<\/th>\n<\/tr>\n<\/thead>\n
25\u5206\u306815\u5206\u304c\u5b8c\u4e86\u300150\u5206\u306f\u672a\u5b8c\u4e86<\/td>\n2\u4ef6<\/td>\n40\u5206<\/td>\n<\/tr>\n
\u672a\u5b8c\u4e86\u3060\u3051<\/td>\n0\u4ef6<\/td>\n0\u5206<\/td>\n<\/tr>\n
\u8a18\u9332\u304c\u306a\u3044<\/td>\n0\u4ef6<\/td>\n0\u5206<\/td>\n<\/tr>\n
\u5b8c\u4e86\u3057\u305f\u8a18\u9332\u306e\u6642\u9593\u304c0<\/td>\n1\u4ef6<\/td>\n0\u5206<\/td>\n<\/tr>\n
`done`\u304c\u6587\u5b57\u5217\u306e`true`<\/td>\n\u5bfe\u8c61\u5916<\/td>\n\u5bfe\u8c61\u5916<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u3053\u306e\u7d04\u675f\u3092\u5f8c\u304b\u3089\u5909\u66f4\u3059\u308b\u306a\u3089\u3001\u671f\u5f85\u7d50\u679c\u3082\u898b\u76f4\u3059\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002AI\u304c\u6c17\u3092\u5229\u304b\u305b\u3066\u300c`done`\u304c\u6587\u5b57\u5217\u3067\u3082\u5b8c\u4e86\u3068\u6271\u3046\u300d\u3088\u3046\u5909\u66f4\u3059\u308b\u3068\u3001\u4eca\u56de\u306f\u5143\u306e\u4ed5\u69d8\u304b\u3089\u5916\u308c\u307e\u3059\u3002<\/p>\n

\u6e96\u5099\uff1aNode.js\u3067\u52d5\u304f\u5c0f\u3055\u306a\u95a2\u6570\u3092\u4fdd\u5b58\u3059\u308b<\/h2>\n

Node.js\u306fJavaScript\u3092\u30d6\u30e9\u30a6\u30b6\u4ee5\u5916\u3067\u3082\u5b9f\u884c\u3067\u304d\u308b\u74b0\u5883\u3067\u3059\u3002Node.js 22\u4ee5\u964d\u3092\u7528\u610f\u3057\u3001\u30bf\u30fc\u30df\u30ca\u30eb\u3067`node –version`\u3092\u5b9f\u884c\u3057\u3066\u78ba\u8a8d\u3057\u3066\u304f\u3060\u3055\u3044\u3002\u4ed5\u4e8b\u7528\u306e\u30d5\u30a1\u30a4\u30eb\u3092\u76f4\u63a5\u66f8\u304d\u63db\u3048\u305a\u3001\u7a7a\u306e\u7df4\u7fd2\u30d5\u30a9\u30eb\u30c0\u306b`study-summary.cjs`\u3092\u4f5c\u308a\u307e\u3059\u3002<\/p>\n

function summarizeStudy(records) {\r\n  let minutes = 0;\r\n  let completed = 0;\r\n  for (const record of records) {\r\n    if (record.done === true) {\r\n      completed += 1;\r\n      minutes += record.minutes;\r\n    }\r\n  }\r\n  return { completed, minutes };\r\n}\r\nmodule.exports = { summarizeStudy };<\/code><\/pre>\n
\u3053\u306e\u51e6\u7406\u306f\u914d\u5217\u3092\u5148\u982d\u304b\u3089\u8aad\u307f\u3001`done === true`\u306e\u3068\u304d\u3060\u3051\u4ef6\u6570\u3068\u6642\u9593\u3092\u5897\u3084\u3057\u307e\u3059\u3002\u623b\u308a\u5024\u306f`{ completed, minutes }`\u3068\u3044\u30462\u3064\u306e\u6570\u5b57\u3092\u6301\u3064\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3067\u3059\u3002<\/p>\n
\u30c6\u30b9\u30c8\u3092\u66f8\u304f\uff1a\u6700\u521d\u306b\u671f\u5f85\u3059\u308b\u7b54\u3048\u3092\u56fa\u5b9a\u3059\u308b<\/h2>\n
\u540c\u3058\u30d5\u30a9\u30eb\u30c0\u306b`study-summary.test.cjs`\u3092\u4f5c\u308a\u3001\u6b21\u306e\u30b3\u30fc\u30c9\u3092\u4fdd\u5b58\u3057\u307e\u3059\u3002`node:test`\u306fNode.js\u306b\u7d44\u307f\u8fbc\u307e\u308c\u305f\u30c6\u30b9\u30c8\u6a5f\u80fd\u3067\u3001`node:assert\/strict`\u306f\u5b9f\u969b\u306e\u5024\u3068\u671f\u5f85\u5024\u304c\u4e00\u81f4\u3059\u308b\u304b\u78ba\u304b\u3081\u308b\u305f\u3081\u306e\u6a5f\u80fd\u3067\u3059\u3002\u5225\u9014`npm install`\u3059\u308b\u5fc5\u8981\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n
const test = require('node:test');\r\nconst assert = require('node:assert\/strict');\r\nconst { summarizeStudy } = require('.\/study-summary.cjs');\r\n\r\ntest('\u5b8c\u4e86\u6e08\u307f\u3060\u3051\u3092\u5408\u8a08\u3059\u308b', () => {\r\n  const records = [\r\n    { done: true, minutes: 25 },\r\n    { done: false, minutes: 50 },\r\n    { done: true, minutes: 15 },\r\n  ];\r\n  assert.deepStrictEqual(summarizeStudy(records), { completed: 2, minutes: 40 });\r\n});\r\n\r\ntest('\u3059\u3079\u3066\u672a\u5b8c\u4e86\u306a\u30890\u4ef6\u30fb0\u5206', () => {\r\n  assert.deepStrictEqual(summarizeStudy([{ done: false, minutes: 20 }]),\r\n    { completed: 0, minutes: 0 });\r\n});\r\n\r\ntest('\u7a7a\u306e\u914d\u5217\u306a\u30890\u4ef6\u30fb0\u5206', () => {\r\n  assert.deepStrictEqual(summarizeStudy([]), { completed: 0, minutes: 0 });\r\n});\r\n\r\ntest('\u5b8c\u4e860\u5206\u30821\u4ef6\u3068\u3057\u3066\u6570\u3048\u308b', () => {\r\n  assert.deepStrictEqual(summarizeStudy([{ done: true, minutes: 0 }]),\r\n    { completed: 1, minutes: 0 });\r\n});\r\n\r\ntest('\u6587\u5b57\u5217\u306edone\u306f\u5b8c\u4e86\u3068\u307f\u306a\u3055\u306a\u3044', () => {\r\n  assert.deepStrictEqual(summarizeStudy([\r\n    { done: 'true', minutes: 99 }, { done: true, minutes: 10 },\r\n  ]), { completed: 1, minutes: 10 });\r\n});<\/code><\/pre>\n
\u30bf\u30fc\u30df\u30ca\u30eb\u3067\u6b21\u3092\u5b9f\u884c\u3057\u307e\u3059\u3002\u30c6\u30b9\u30c8\u5bfe\u8c61\u3068\u30c6\u30b9\u30c8\u30d5\u30a1\u30a4\u30eb\u306f\u540c\u3058\u30d5\u30a9\u30eb\u30c0\u306b\u7f6e\u3044\u3066\u304f\u3060\u3055\u3044\u3002<\/p>\n
node --test study-summary.test.cjs<\/code><\/pre>\n
\u3053\u306e\u30b5\u30f3\u30d7\u30eb\u3067\u306f5\u4ef6\u306e\u30c6\u30b9\u30c8\u304cPASS<\/strong>\u3059\u308b\u3053\u3068\u3092\u78ba\u8a8d\u6e08\u307f\u3067\u3059\u3002\u753b\u9762\u4e0a\u306e\u8868\u793a\u5f62\u5f0f\u306fNode.js\u306e\u30d0\u30fc\u30b8\u30e7\u30f3\u3067\u591a\u5c11\u7570\u306a\u308a\u307e\u3059\u3002\u91cd\u8981\u306a\u306e\u306f\u3001\u5931\u6557\u3057\u305f\u30c6\u30b9\u30c8\u304c\u306a\u3044\u3053\u3068\u3068\u3001\u5bfe\u8c61\u306e\u5165\u529b\u30fb\u671f\u5f85\u7d50\u679c\u3092\u81ea\u5206\u3067\u8aad\u3081\u308b\u3053\u3068\u3067\u3059\u3002<\/p>\n
\uff08\u30c6\u30b9\u30c8\u30e9\u30f3\u30ca\u30fc\u306e\u69cb\u6587\u306b\u3064\u3044\u3066\u306f\u300eNode.js\u516c\u5f0fTest runner<\/a>\u300f\u3092\u3054\u53c2\u7167\u304f\u3060\u3055\u3044\uff09<\/p>\n
\u5185\u90e8\u3092\u66f8\u304d\u63db\u3048\u3001\u540c\u3058\u30c6\u30b9\u30c8\u3092\u3082\u3046\u4e00\u5ea6\u52d5\u304b\u3059<\/h2>\n
`study-summary.cjs`\u306e\u5185\u5bb9\u3060\u3051\u3092\u3001\u6b21\u306e\u30b3\u30fc\u30c9\u306b\u7f6e\u304d\u63db\u3048\u307e\u3059\u3002\u5b8c\u4e86\u6e08\u307f\u306e\u8a18\u9332\u3092`filter`\u3067\u9078\u3073\u3001`reduce`\u3067\u5206\u6570\u3092\u5408\u8a08\u3059\u308b\u5b9f\u88c5\u306b\u5909\u66f4\u3057\u307e\u3057\u305f\u3002\u30c6\u30b9\u30c8\u30d5\u30a1\u30a4\u30eb\u3068\u671f\u5f85\u7d50\u679c\u306f\u5909\u3048\u307e\u305b\u3093\u3002<\/p>\n
function summarizeStudy(records) {\r\n  const finished = records.filter((record) => record.done === true);\r\n  return {\r\n    completed: finished.length,\r\n    minutes: finished.reduce((total, record) => total + record.minutes, 0),\r\n  };\r\n}\r\nmodule.exports = { summarizeStudy };<\/code><\/pre>\n
`reduce`\u306e\u6700\u5f8c\u306b\u3042\u308b`0`\u306f\u5408\u8a08\u306e\u521d\u671f\u5024\u3067\u3059\u3002\u3053\u308c\u304c\u3042\u308b\u305f\u3081\u3001\u5b8c\u4e86\u3057\u305f\u8a18\u9332\u304c0\u4ef6\u3067\u3082\u5408\u8a08\u30920\u3068\u3057\u3066\u8fd4\u305b\u307e\u3059\u3002\u3053\u3053\u3092\u7701\u304f\u3068\u7a7a\u306e\u914d\u5217\u306b\u5bfe\u3059\u308b\u51e6\u7406\u3067\u5931\u6557\u3059\u308b\u305f\u3081\u3001\u898b\u305f\u76ee\u3060\u3051\u3067\u524a\u9664\u3057\u306a\u3044\u3067\u304f\u3060\u3055\u3044\u3002<\/p>\n
node --test study-summary.test.cjs<\/code><\/pre>\n
\u3053\u306e\u66f8\u304d\u63db\u3048\u5f8c\u3082\u3001\u7528\u610f\u3057\u305f5\u4ef6\u306e\u30c6\u30b9\u30c8\u304cPASS\u3059\u308b\u3053\u3068\u3092\u5b9f\u884c\u78ba\u8a8d\u3057\u307e\u3057\u305f\u3002\u3053\u308c\u306f\u300c\u4eca\u56de\u306e5\u6761\u4ef6\u3067\u7d50\u679c\u304c\u4e00\u81f4\u3057\u305f\u300d\u3068\u3044\u3046\u8a3c\u62e0\u3067\u3042\u308a\u3001\u3042\u3089\u3086\u308b\u5165\u529b\u306e\u52d5\u4f5c\u3092\u4fdd\u8a3c\u3059\u308b\u3082\u306e\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n
AI\u306e\u5909\u66f4\u304c\u539f\u56e0\u3067\u30c6\u30b9\u30c8\u304c\u843d\u3061\u305f\u3089\u3069\u3046\u3059\u308b\uff1f<\/h2>\n
\u4f8b\u3048\u3070\u3001`record.done === true`\u3092`record.done`\u306b\u5909\u3048\u308b\u3068\u3001\u771f\u507d\u5024\u3067\u306f\u306a\u3044`"true"`\u3068\u3044\u3046\u6587\u5b57\u5217\u3082\u5b8c\u4e86\u3068\u3057\u3066\u6570\u3048\u3089\u308c\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002\u898b\u305f\u76ee\u306f\u308f\u305a\u304b\u306a\u9055\u3044\u3067\u3082\u3001\u96c6\u8a08\u4ef6\u6570\u304c\u5909\u308f\u308a\u307e\u3059\u3002<\/p>\n
const finished = records.filter((record) => record.done);<\/code><\/pre>\n
\u672c\u4f8b\u306e\u300c\u6587\u5b57\u5217\u306edone\u306f\u5b8c\u4e86\u3068\u307f\u306a\u3055\u306a\u3044\u300d\u3068\u3044\u3046\u30c6\u30b9\u30c8\u306f\u3001\u305d\u306e\u3088\u3046\u306a\u5909\u66f4\u3092\u691c\u51fa\u3057\u307e\u3059\u3002\u610f\u56f3\u7684\u306b\u3053\u306e\u8aa4\u3063\u305f\u6761\u4ef6\u306b\u3057\u305f\u969b\u30015\u4ef6\u4e2d1\u4ef6\u304cFAIL\u3059\u308b\u3053\u3068\u3082\u5b9f\u884c\u78ba\u8a8d\u3057\u307e\u3057\u305f\u3002<\/p>\n
    \n
  1. \u307e\u305a\u5931\u6557\u3057\u305f\u30c6\u30b9\u30c8\u540d\u3068\u671f\u5f85\u5024\u30fb\u5b9f\u969b\u306e\u5024\u3092\u8aad\u3080\u3002<\/li>\n
  2. \u3069\u306e\u6761\u4ef6\u3092\u5909\u3048\u305f\u304b\u3001\u8a72\u5f53\u3059\u308b\u30b3\u30fc\u30c9\u884c\u3092\u898b\u3064\u3051\u308b\u3002<\/li>\n
  3. \u4ed5\u69d8\u5909\u66f4\u306e\u4f9d\u983c\u304c\u306a\u3051\u308c\u3070\u3001\u3082\u3068\u306e\u610f\u5473\u3092\u4fdd\u3064\u3088\u3046\u4fee\u6b63\u3057\u3066\u518d\u5b9f\u884c\u3059\u308b\u3002<\/li>\n<\/ol>\n
    \u4ed5\u69d8\u305d\u306e\u3082\u306e\u3092\u5909\u3048\u308b\u5fc5\u8981\u304c\u3042\u308b\u5834\u5408\u306f\u3001\u5909\u66f4\u7406\u7531\u3068\u65b0\u3057\u3044\u671f\u5f85\u7d50\u679c\u3092\u5225\u306b\u691c\u8a0e\u3057\u307e\u3059\u3002\u300c\u30c6\u30b9\u30c8\u304c\u843d\u3061\u305f\u304b\u3089\u671f\u5f85\u5024\u3092\u66f8\u304d\u63db\u3048\u308b\u300d\u3060\u3051\u3067\u306f\u3001\u554f\u984c\u306e\u898b\u843d\u3068\u3057\u306b\u3064\u306a\u304c\u308a\u307e\u3059\u3002<\/p>\n
    \u901a\u3063\u305f\u5f8c\u306b\u898b\u308b\u3053\u3068\u3068\u3001\u30c6\u30b9\u30c8\u3060\u3051\u3067\u306f\u5206\u304b\u3089\u306a\u3044\u3053\u3068<\/h2>\n