{"id":205,"date":"2026-03-09T20:20:17","date_gmt":"2026-03-09T20:20:17","guid":{"rendered":"https:\/\/blog.rebalai.com\/ja\/2026\/03\/09\/typescript-5x-in-2026-features-that-actually-matte\/"},"modified":"2026-03-09T22:00:14","modified_gmt":"2026-03-09T22:00:14","slug":"typescript-5x-in-2026-features-that-actually-matte","status":"publish","type":"post","link":"https:\/\/blog.rebalai.com\/ja\/2026\/03\/09\/typescript-5x-in-2026-features-that-actually-matte\/","title":{"rendered":"TypeScript 5.x 2026\u5e74: \u672c\u756a\u30b3\u30fc\u30c9\u3067\u672c\u5f53\u306b\u91cd\u8981\u306a\u6a5f\u80fd"},"content":{"rendered":"<p>TypeScript 5.0\u304c\u51fa\u305f\u306e\u306f2023\u5e743\u6708\u3060\u3063\u305f\u3002\u305d\u308c\u304b\u30893\u5e74\u8fd1\u304f\u30015.8\u307e\u3067\u8ffd\u3044\u304b\u3051\u3066\u304d\u305f\u3002\u6bce\u56de\u30ea\u30ea\u30fc\u30b9\u30ce\u30fc\u30c8\u3092\u8aad\u3093\u3067\u300c\u3078\u3048\u3001\u304a\u3082\u3057\u308d\u3044\u300d\u3068\u601d\u3046\u3093\u3060\u3051\u3069\u3001\u6b63\u76f4\u5927\u534a\u306e\u6a5f\u80fd\u306f\u305d\u3053\u3067\u7d42\u308f\u308b\u3002\u8a66\u3057\u3066\u307f\u3066\u3001\u30b3\u30fc\u30c9\u3092\u66f8\u304d\u63db\u3048\u308b\u307b\u3069\u3067\u3082\u306a\u3044\u306a\u3001\u3068\u5224\u65ad\u3057\u3066\u6b21\u306e\u30b9\u30d7\u30ea\u30f3\u30c8\u306b\u623b\u308b\u3002<\/p>\n<p>\u3067\u3082\u4e00\u90e8\u306f\u9055\u3063\u305f\u3002\u5b9f\u969b\u306b\u4ed5\u4e8b\u306e\u3084\u308a\u65b9\u304c\u5909\u308f\u3063\u305f\u6a5f\u80fd\u304c\u3042\u308b\u3002<\/p>\n<p>\u81ea\u5206\u306e\u30b9\u30bf\u30c3\u30af\u3092\u66f8\u3044\u3066\u304a\u304f: 5\u4eba\u30c1\u30fc\u30e0\u3067SaaS\u30d7\u30ed\u30c0\u30af\u30c8\u3092\u4f5c\u3063\u3066\u3044\u308b\u3002Next.js + tRPC + Prisma\u3001\u30c7\u30d7\u30ed\u30a4\u306fVercel + Railway\u3002TypeScript\u306f\u5e38\u306b\u6700\u65b0\u30de\u30a4\u30ca\u30fc\u30d0\u30fc\u30b8\u30e7\u30f3\u3092\u8ffd\u3044\u304b\u3051\u3066\u3044\u3066\u3001\u4eca\u306f5.8\u3092\u672c\u756a\u3067\u4f7f\u3063\u3066\u3044\u308b\u3002\u4eca\u56de\u66f8\u304f\u306e\u306f\u3001\u305d\u306e\u30b3\u30fc\u30c9\u30d9\u30fc\u30b9\u3067\u300c\u672c\u5f53\u306b\u5dee\u304c\u51fa\u305f\u300d\u3068\u611f\u3058\u305f4\u3064\u306e\u6a5f\u80fd\u3060\u3002\u30d0\u30ba\u3063\u305f\u3051\u3069\u4f7f\u3044\u3069\u3053\u308d\u304c\u72ed\u304b\u3063\u305f\u3084\u3064\u306f\u610f\u56f3\u7684\u306b\u5916\u3057\u305f\u3002<\/p>\n<hr \/>\n<h2><code>using<\/code>\u5ba3\u8a00\u3067\u30ea\u30bd\u30fc\u30b9\u30ea\u30fc\u30af\u7cfb\u306e\u30d0\u30b0\u304c1\u30af\u30e9\u30b9\u307e\u308b\u3054\u3068\u6d88\u3048\u305f<\/h2>\n<p>TypeScript 5.2\u3067\u5165\u3063\u305f<code>using<\/code>\u5ba3\u8a00\u3001\u6700\u521d\u898b\u305f\u3068\u304d\u300cC#\u306eusing\u3058\u3083\u3093\u300d\u3068\u601d\u3063\u305f\u3060\u3051\u3067\u7279\u306b\u6c17\u306b\u3057\u3066\u3044\u306a\u304b\u3063\u305f\u3002\u8003\u3048\u304c\u5909\u308f\u3063\u305f\u306e\u306f2024\u5e74\u306e\u590f\u3001\u672c\u756a\u3067\u63a5\u7d9a\u30d7\u30fc\u30eb\u304c\u67af\u6e07\u3059\u308b\u4e8b\u4ef6\u304c\u8d77\u304d\u3066\u304b\u3089\u3002<\/p>\n<p>\u30ed\u30b0\u3092\u6570\u6642\u9593\u8ffd\u3063\u305f\u3089\u3001\u30d0\u30c3\u30af\u30b0\u30e9\u30a6\u30f3\u30c9\u30b8\u30e7\u30d6\u306e\u3072\u3068\u3064\u3067<code>finally<\/code>\u30d6\u30ed\u30c3\u30af\u304c\u629c\u3051\u3066\u3044\u305f\u3002\u30a8\u30e9\u30fc\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0\u3092\u8ffd\u52a0\u3059\u308b\u3068\u304d\u306b\u8ab0\u304b\u304c<code>finally<\/code>\u3092\u6d88\u3057\u3066\u3057\u307e\u3063\u3066\u3044\u3066\u3001\u30ec\u30d3\u30e5\u30fc\u3067\u3082\u898b\u843d\u3068\u3057\u305f\u3002\u305d\u306e\u30b8\u30e7\u30d6\u304c\u9577\u6642\u9593\u7a3c\u50cd\u3057\u3066\u3044\u305f\u305b\u3044\u3067\u63a5\u7d9a\u304c\u623b\u3089\u306a\u304f\u306a\u3063\u3066\u3044\u305f\u3002\u624b\u75db\u3044\u6848\u4ef6\u3060\u3063\u305f\u3002<\/p>\n<p>\u554f\u984c\u306b\u306a\u3063\u3066\u3044\u305f\u30b3\u30fc\u30c9\u306e\u30d1\u30bf\u30fc\u30f3:<\/p>\n<pre><code class=\"language-typescript\">\/\/ before: try\u306e\u3069\u3053\u304b\u3067throw\u3059\u308b\u3068\u63a5\u7d9a\u304c\u623b\u3089\u306a\u3044\u3053\u3068\u304c\u3042\u308b\nasync function processJob(jobId: string) {\n  const client = await pool.connect();\n  try {\n    await client.query('BEGIN');\n    const result = await doHeavyWork(client, jobId);\n    await client.query('COMMIT');\n    return result;\n  } catch (e) {\n    await client.query('ROLLBACK');\n    throw e;\n  } finally {\n    client.release(); \/\/ \u3053\u308c\u3092\u66f8\u304d\u5fd8\u308c\u308b\u3001\u3042\u308b\u3044\u306f\u524a\u9664\u3055\u308c\u308b\u3053\u3068\u304c\u5b9f\u969b\u306b\u3042\u308b\n  }\n}\n<\/code><\/pre>\n<p><code>using<\/code>\u306b\u5207\u308a\u66ff\u3048\u308b\u306b\u306f\u3001<code>Symbol.dispose<\/code>\u3092\u5b9f\u88c5\u3057\u305f\u30e9\u30c3\u30d1\u30fc\u3092\u4e00\u5ea6\u66f8\u304f:<\/p>\n<pre><code class=\"language-typescript\">class ManagedClient {\n  constructor(private client: PoolClient) {}\n\n  get query() {\n    return this.client.query.bind(this.client);\n  }\n\n  [Symbol.dispose]() {\n    \/\/ \u30b9\u30b3\u30fc\u30d7\u3092\u629c\u3051\u308b\u3068\u304d\u306b\u5fc5\u305a\u547c\u3070\u308c\u308b\n    this.client.release();\n  }\n}\n\nasync function processJob(jobId: string) {\n  using managed = new ManagedClient(await pool.connect());\n  \/\/ return\/throw\/\u3069\u3093\u306a\u7d4c\u8def\u3067\u3082\u3001\u30b9\u30b3\u30fc\u30d7\u3092\u51fa\u305f\u3089release()\u304c\u8d70\u308b\n  await managed.query('BEGIN');\n  const result = await doHeavyWork(managed, jobId);\n  await managed.query('COMMIT');\n  return result;\n}\n<\/code><\/pre>\n<p><code>finally<\/code>\u3092\u66f8\u304d\u5fd8\u308c\u308b\u3068\u3044\u3046\u30d0\u30b0\u306e\u30af\u30e9\u30b9\u3054\u3068\u6d88\u3048\u305f\u3002\u30b3\u30fc\u30c9\u30ec\u30d3\u30e5\u30fc\u3067\u300c\u3042\u3001finally\u304c\u306a\u3044\u300d\u3068\u6307\u6458\u3059\u308b\u5fc5\u8981\u304c\u306a\u304f\u306a\u3063\u305f\u3002<\/p>\n<p>\u6ce8\u610f\u70b9: Prisma\u305d\u306e\u3082\u306e\u306f\u307e\u3060<code>Symbol.dispose<\/code>\u3092\u5b9f\u88c5\u3057\u3066\u3044\u306a\u3044\u306e\u3067\u3001\u30e9\u30c3\u30d1\u30fc\u306f\u81ea\u5206\u3067\u66f8\u304f\u5fc5\u8981\u304c\u3042\u308b\u3002\u975e\u540c\u671f\u306eclose\u304c\u5fc5\u8981\u306a\u30ea\u30bd\u30fc\u30b9\u306b\u306f<code>await using<\/code>\u3068<code>Symbol.asyncDispose<\/code>\u3092\u4f7f\u3046\u3002\u6700\u521d\u306e\u30e9\u30c3\u30d1\u30fc\u3092\u66f8\u304f\u30b3\u30b9\u30c8\u306f\u304b\u304b\u308b\u3051\u3069\u30011\u56de\u66f8\u3051\u3070\u30c1\u30fc\u30e0\u5168\u4f53\u3067\u518d\u5229\u7528\u3067\u304d\u308b\u3002\u3046\u3061\u3067\u306f<code>ManagedClient<\/code>\u3092\u66f8\u3044\u305f\u7fcc\u9031\u306b\u306f\u3001\u540c\u3058\u30d1\u30bf\u30fc\u30f3\u3067\u5225\u306e\u30ea\u30bd\u30fc\u30b9\u7ba1\u7406\u30b3\u30fc\u30c9\u304c\u81ea\u7136\u306b\u5897\u3048\u3066\u3044\u305f\u3002<\/p>\n<hr \/>\n<h2><code>NoInfer&lt;T&gt;<\/code>: \u534a\u5e74\u9593\u6c17\u3065\u304b\u306a\u304b\u3063\u305f\u578b\u8a2d\u8a08\u306e\u7a74\u3092\u585e\u3044\u3060<\/h2>\n<p>TypeScript 5.4\u306e<code>NoInfer&lt;T&gt;<\/code>\u306f\u3001\u30ea\u30ea\u30fc\u30b9\u6642\u306b\u5b8c\u5168\u306b\u898b\u9003\u3057\u305f\u3002\u6c17\u3065\u3044\u305f\u306e\u306fGitHub\u306eissue\u3092\u305f\u307e\u305f\u307e\u8aad\u3093\u3067\u3044\u305f\u3068\u304d\u3067\u30015.4\u304c\u51fa\u3066\u304b\u30894\u30f6\u6708\u304f\u3089\u3044\u5f8c\u3002<\/p>\n<p>\u300c\u306a\u3093\u3067\u3053\u3093\u306a\u6a5f\u80fd\u304c\u5fc5\u8981\u306a\u3093\u3060?\u300d\u3068\u6700\u521d\u306f\u601d\u3063\u305f\u3093\u3060\u3051\u3069\u3001\u81ea\u5206\u306e\u30b3\u30fc\u30c9\u3092\u898b\u8fd4\u3057\u305f\u30893\u7b87\u6240\u3067\u540c\u3058\u554f\u984c\u3092\u62b1\u3048\u3066\u3044\u305f\u3002\u300c\u534a\u5e74\u9593\u3053\u308c\u3067\u56f0\u3063\u3066\u305f\u306e\u304b\u300d\u3068\u5c11\u3057\u3052\u3093\u306a\u308a\u3057\u305f\u3002<\/p>\n<p>\u3053\u3046\u3044\u3046\u72b6\u6cc1\u3092\u60f3\u50cf\u3057\u3066\u307b\u3057\u3044\u3002\u30b8\u30a7\u30cd\u30ea\u30c3\u30af\u95a2\u6570\u3092\u66f8\u3044\u3066\u3044\u3066\u3001\u300c\u578b\u30d1\u30e9\u30e1\u30fc\u30bf\u306f\u3042\u308b\u5f15\u6570\u304b\u3089\u63a8\u8ad6\u3057\u3066\u307b\u3057\u3044\u304c\u3001\u5225\u306e\u5f15\u6570\u304b\u3089\u306f\u63a8\u8ad6\u3057\u3066\u307b\u3057\u304f\u306a\u3044\u300d\u3068\u3044\u3046\u30b1\u30fc\u30b9:<\/p>\n<pre><code class=\"language-typescript\">\/\/ \u554f\u984c: allowedValues\u3068defaultValue\u306e\u4e21\u65b9\u304b\u3089T\u3092\u63a8\u8ad6\u3059\u308b\nfunction createSelect&lt;T&gt;(\n  allowedValues: T[],\n  defaultValue: T\n): SelectConfig&lt;T&gt; { ... }\n\n\/\/ \u610f\u56f3: 'extra-large'\u306f\u3042\u308a\u3048\u306a\u3044\u306e\u3067\u30a8\u30e9\u30fc\u306b\u3057\u305f\u3044\n\/\/ \u5b9f\u969b: TypeScript\u304c T = &quot;small&quot; | &quot;medium&quot; | &quot;large&quot; | &quot;extra-large&quot; \u306b\u62e1\u5f35\u3057\u3066\u3057\u307e\u3046\ncreateSelect(['small', 'medium', 'large'], 'extra-large'); \/\/ \u30a8\u30e9\u30fc\u306b\u306a\u3089\u306a\u3044\n<\/code><\/pre>\n<p><code>NoInfer&lt;T&gt;<\/code>\u3092\u4f7f\u3046\u3068\u3001\u6307\u5b9a\u3057\u305f\u5f15\u6570\u3092\u578b\u63a8\u8ad6\u306e\u5bfe\u8c61\u304b\u3089\u9664\u5916\u3067\u304d\u308b:<\/p>\n<pre><code class=\"language-typescript\">function createSelect&lt;T&gt;(\n  allowedValues: T[],\n  defaultValue: NoInfer&lt;T&gt; \/\/ \u2190T\u306e\u63a8\u8ad6\u30bd\u30fc\u30b9\u304b\u3089\u9664\u5916\n): SelectConfig&lt;T&gt; {\n  if (!allowedValues.includes(defaultValue)) {\n    throw new Error(`Invalid default: ${String(defaultValue)}`);\n  }\n  return { allowedValues, defaultValue };\n}\n\n\/\/ \u4eca\u5ea6\u306f\u3061\u3083\u3093\u3068\u30b3\u30f3\u30d1\u30a4\u30eb\u30a8\u30e9\u30fc\u306b\u306a\u308b\ncreateSelect(['small', 'medium', 'large'], 'extra-large');\n\/\/ Argument of type '&quot;extra-large&quot;' is not assignable to parameter of type 'NoInfer&lt;...&gt;'\n<\/code><\/pre>\n<p>\u3046\u3061\u306e\u30b3\u30fc\u30c9\u30d9\u30fc\u30b9\u3067\u306f\u3001\u8a2d\u5b9a\u30d3\u30eb\u30c0\u30fc\u306eAPI\u306b\u3053\u306e\u30d1\u30bf\u30fc\u30f3\u304c3\u7b87\u6240\u3042\u3063\u305f\u3002\u9069\u7528\u3057\u3066\u304b\u3089\u578b\u30c1\u30a7\u30c3\u30af\u3092\u8d70\u3089\u305b\u305f\u3089\u3001\u672c\u756a\u30b3\u30fc\u30c9\u3067\u300c\u3042\u308a\u3048\u306a\u3044\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u304c\u8a2d\u5b9a\u3055\u308c\u3066\u3044\u305f\u300d\u30d0\u30b0\u304c1\u4ef6\u898b\u3064\u304b\u3063\u305f\u3002\u30e9\u30f3\u30bf\u30a4\u30e0\u306e\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u3067\u9632\u3044\u3067\u3044\u305f\u3051\u3069\u3001\u578b\u30ec\u30d9\u30eb\u3067\u9632\u3052\u3066\u3044\u306a\u304b\u3063\u305f\u3084\u3064\u3060\u3002<\/p>\n<p>\u30e9\u30a4\u30d6\u30e9\u30ea\u3092\u66f8\u3044\u3066\u3044\u308b\u4eba\u3084API\u30c7\u30b6\u30a4\u30f3\u306b\u3053\u3060\u308f\u308a\u306e\u3042\u308b\u4eba\u307b\u3069\u6069\u6075\u304c\u5927\u304d\u3044\u6a5f\u80fd\u3060\u3068\u601d\u3046\u3002\u30a2\u30d7\u30ea\u30b1\u30fc\u30b7\u30e7\u30f3\u30b3\u30fc\u30c9\u3060\u3051\u66f8\u3044\u3066\u3044\u308b\u4eba\u306f\u300c\u3042\u3063\u3066\u3088\u304b\u3063\u305f\u300d\u304f\u3089\u3044\u304b\u3082\u3057\u308c\u306a\u3044\u3002\u3067\u3082\u8a72\u5f53\u3059\u308b\u30d1\u30bf\u30fc\u30f3\u304c\u3042\u308b\u306a\u3089\u3001\u898b\u3064\u3051\u305f\u77ac\u9593\u306b\u76f4\u3057\u305f\u304f\u306a\u308b\u3002\u300c\u81ea\u5206\u306b\u306f\u95a2\u4fc2\u306a\u3044\u300d\u3068\u601d\u3063\u305f\u4eba\u3082\u3001\u6b21\u306b\u30b8\u30a7\u30cd\u30ea\u30c3\u30af\u95a2\u6570\u3092\u66f8\u304f\u3068\u304d\u4e00\u5ea6\u7acb\u3061\u6b62\u307e\u3063\u3066\u307f\u3066\u307b\u3057\u3044\u3002\u6848\u5916\u3042\u308b\u3002<\/p>\n<hr \/>\n<h2>\u578b\u8ff0\u8a9e\u306e\u81ea\u52d5\u63a8\u8ad6: \u6c17\u3065\u3044\u305f\u3089\u65e2\u5b58\u30b3\u30fc\u30c9\u304c7\u500b\u6d88\u3048\u3066\u3044\u305f<\/h2>\n<p>\u3053\u308c\u306f\u672c\u5f53\u306b\u4e88\u60f3\u3057\u3066\u3044\u306a\u304b\u3063\u305f\u3002<\/p>\n<p>TypeScript 5.5\u306e\u300cInferred Type Predicates\u300d\u304c\u4fbf\u5229\u305d\u3046\u3068\u3044\u3046\u306e\u306f\u77e5\u3063\u3066\u3044\u305f\u3093\u3060\u3051\u3069\u3001\u5b9f\u611f\u3057\u305f\u306e\u306f5.5\u306b\u4e0a\u3052\u3066\u3057\u3070\u3089\u304f\u5f8c\u306e\u30b3\u30fc\u30c9\u30ec\u30d3\u30e5\u30fc\u3060\u3063\u305f\u3002\u540c\u50da\u304c\u66f8\u3044\u305fPR\u3092\u8aad\u3093\u3067\u3044\u305f\u3089\u3001\u3053\u3046\u3044\u3046\u30b3\u30fc\u30c9\u304c\u3042\u3063\u305f:<\/p>\n<pre><code class=\"language-typescript\">const activeUsers = users.filter(user =&gt; user.isActive &amp;&amp; user.email !== null);\n\/\/ email\u304cstring | null\u3060\u3063\u305f\u306e\u304c\u3001TypeScript\u304cstring\u578b\u3068\u3057\u3066\u63a8\u8ad6\u3057\u3066\u3044\u305f\n<\/code><\/pre>\n<p>\u300c\u3042\u308c\u3001\u3053\u308c\u3063\u30665.4\u4ee5\u524d\u3060\u3063\u305f\u3089\u578b\u8ff0\u8a9e\u30d8\u30eb\u30d1\u30fc\u304c\u5fc5\u8981\u306a\u3084\u3064\u3058\u3083\u306a\u304b\u3063\u305f\u3063\u3051\u300d\u3068\u601d\u3063\u3066\u78ba\u8a8d\u3057\u305f\u3089\u3001\u305d\u3046\u3060\u3063\u305f\u30025.5\u4ee5\u964d\u306f\u3001filter\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u306e\u8fd4\u308a\u5024\u306e\u578b\u304b\u3089TypeScript\u304c\u81ea\u52d5\u3067\u578b\u8ff0\u8a9e\u3092\u5c0e\u3044\u3066\u304f\u308c\u308b\u3002\u3064\u307e\u308a\u3001\u3053\u3046\u3044\u3046\u30d8\u30eb\u30d1\u30fc\u95a2\u6570\u306e\u5b58\u5728\u610f\u7fa9\u304c\u306a\u304f\u306a\u3063\u305f:<\/p>\n<pre><code class=\"language-typescript\">\/\/ 5.4\u4ee5\u524d\u306e\u30b3\u30fc\u30c9\u30d9\u30fc\u30b9\u306b\u6563\u3089\u3070\u3063\u3066\u3044\u305f\u3084\u3064\nfunction isNonNullString(v: string | null | undefined): v is string {\n  return v !== null &amp;&amp; v !== undefined;\n}\n\nfunction isActiveUser(u: User | null): u is User {\n  return u !== null &amp;&amp; u.isActive === true;\n}\n\/\/ ...\u4ee5\u4e0b\u7d9a\u304f\n<\/code><\/pre>\n<p>5.5\u306b\u4e0a\u3052\u305f\u5f8c\u3001\u65e2\u5b58\u306e\u3053\u3046\u3044\u3046\u30d8\u30eb\u30d1\u30fc\u95a2\u6570\u3092\u78ba\u8a8d\u3057\u3066\u307f\u305f\u3089\u30017\u3064\u304c\u300c\u3082\u3046\u4e0d\u8981\u300d\u306b\u306a\u3063\u3066\u3044\u305f\u3002\u5927\u91cf\u524a\u9664\u3068\u3044\u3046\u308f\u3051\u3058\u3083\u306a\u3044\u3051\u3069\u30011\u30641\u3064\u304c\u300c\u5909\u66f4\u306e\u305f\u3073\u306b\u30e1\u30f3\u30c6\u304c\u5fc5\u8981\u306a\u578b\u30b3\u30fc\u30c9\u300d\u3060\u3063\u305f\u306e\u3067\u3001\u6d88\u3048\u305f\u306e\u306f\u7d20\u76f4\u306b\u5b09\u3057\u304b\u3063\u305f\u3002<\/p>\n<p>\u5168\u90e8\u304c\u81ea\u52d5\u63a8\u8ad6\u3055\u308c\u308b\u308f\u3051\u3067\u306f\u306a\u3044\u3002<code>instanceof<\/code>\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u8907\u96d1\u306a\u30b1\u30fc\u30b9\u3084\u3001\u5916\u90e8API\u306e\u30ec\u30b9\u30dd\u30f3\u30b9\u691c\u8a3c\u306b\u306f\u624b\u66f8\u304d\u304c\u307e\u3060\u5fc5\u8981\u306a\u3053\u3068\u304c\u3042\u308b\u3002\u3067\u3082\u300c\u3088\u304f\u3042\u308bnull\u30c1\u30a7\u30c3\u30af\u7cfb\u300d\u306f\u307b\u307c\u30ab\u30d0\u30fc\u3055\u308c\u3066\u3044\u308b\u3068\u611f\u3058\u3066\u3044\u308b\u3002<\/p>\n<hr \/>\n<h2><code>--isolatedDeclarations<\/code>\u306f\u30e2\u30ce\u30ec\u30dd\u52e2\u306b\u3060\u3051\u523a\u3055\u308b\u8a71<\/h2>\n<p>\u3053\u308c\u306f\u4eba\u3092\u9078\u3076\u3002\u304b\u306a\u308a\u9078\u3076\u3002\u30b7\u30f3\u30b0\u30eb\u30d1\u30c3\u30b1\u30fc\u30b8\u306e\u30d7\u30ed\u30b8\u30a7\u30af\u30c8\u306b\u306f\u95a2\u4fc2\u306a\u3044\u306e\u3067\u3001\u305d\u3046\u3044\u3046\u4eba\u306f\u3053\u3053\u3092\u8aad\u307f\u98db\u3070\u3057\u3066\u554f\u984c\u306a\u3044\u3002<\/p>\n<p>5.5\u3067\u5165\u3063\u305f<code>--isolatedDeclarations<\/code>\u306f\u3001\u578b\u5ba3\u8a00\u30d5\u30a1\u30a4\u30eb(<code>.d.ts<\/code>)\u306e\u751f\u6210\u3092\u4e26\u5217\u5316\u53ef\u80fd\u306b\u3059\u308b\u30d5\u30e9\u30b0\u3060\u3002\u4ed5\u7d44\u307f\u3092\u4e00\u8a00\u3067\u8a00\u3046\u3068: \u3053\u306e\u30d5\u30e9\u30b0\u3092\u6709\u52b9\u306b\u3059\u308b\u3068\u3001\u5404\u30d1\u30c3\u30b1\u30fc\u30b8\u304c\u81ea\u5206\u306e<code>.d.ts<\/code>\u3092\u751f\u6210\u3059\u308b\u3068\u304d\u306b\u4ed6\u306e\u30d1\u30c3\u30b1\u30fc\u30b8\u306e\u578b\u60c5\u5831\u3092\u53c2\u7167\u3057\u306a\u304f\u3066\u3044\u3044\u72b6\u614b\u306b\u306a\u308b\u3002\u3053\u308c\u304c\u30c4\u30fc\u30eb\u30c1\u30a7\u30fc\u30f3\u5074\u3067\u4e26\u5217\u5316\u306e\u30d2\u30f3\u30c8\u306b\u306a\u308b\u3002<\/p>\n<p>\u305f\u3060\u3057\u6761\u4ef6\u304c\u3042\u308b\u3002\u30a8\u30af\u30b9\u30dd\u30fc\u30c8\u3055\u308c\u308b\u5168\u3066\u306e\u95a2\u6570\u30fb\u5909\u6570\u306b\u660e\u793a\u7684\u306a\u578b\u6ce8\u91c8\u304c\u5fc5\u8981\u306b\u306a\u308b:<\/p>\n<pre><code class=\"language-typescript\">\/\/ isolatedDeclarations\u304c\u6709\u52b9\u3060\u3068\u30a8\u30e9\u30fc: \u623b\u308a\u5024\u578b\u304c\u63a8\u8ad6\u306b\u4f9d\u5b58\u3057\u3066\u3044\u308b\nexport function getUser(id: string) {\n  return prisma.user.findUnique({ where: { id } });\n}\n\n\/\/ \u3053\u3046\u66f8\u304f\u5fc5\u8981\u304c\u3042\u308b\nexport async function getUser(id: string): Promise&lt;User | null&gt; {\n  return prisma.user.findUnique({ where: { id } });\n}\n<\/code><\/pre>\n<p>\u6709\u52b9\u5316\u3057\u305f\u3068\u304d\u3001\u3046\u3061\u306e\u30e2\u30ce\u30ec\u30dd(12\u30d1\u30c3\u30b1\u30fc\u30b8\u3001Turborepo\u3067\u7ba1\u7406)\u3067\u4fee\u6b63\u304c\u5fc5\u8981\u306a\u7b87\u6240\u304c\u7d04230\u3042\u3063\u305f\u3002\u6b63\u76f4\u3001\u60f3\u5b9a\u3088\u308a\u591a\u304b\u3063\u305f\u30021\u65e5\u304b\u3051\u3066\u5bfe\u5fdc\u3057\u305f\u3002\u4f5c\u696d\u81ea\u4f53\u306f\u307b\u307c\u6a5f\u68b0\u7684\u3067\u3001TypeScript\u306e\u30a8\u30e9\u30fc\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u578b\u3092\u63d0\u6848\u3057\u3066\u304f\u308c\u308b\u3053\u3068\u3082\u591a\u304b\u3063\u305f\u3051\u3069\u3001\u5730\u5473\u306b\u75b2\u308c\u308b\u4f5c\u696d\u3060\u3063\u305f\u3002\u9014\u4e2d\u3067\u3084\u3081\u306a\u304b\u3063\u305f\u306e\u306f\u3001\u540c\u50da\u304cCI\u306e\u9045\u3055\u306b\u6bce\u65e5\u307c\u3084\u3044\u3066\u3044\u305f\u306e\u3092\u601d\u3044\u51fa\u3057\u305f\u304b\u3089\u3002<\/p>\n<p>\u7d50\u679c: Turborepo\u306e\u30ad\u30e3\u30c3\u30b7\u30e5\u306a\u3057\u5168\u30d3\u30eb\u30c9\u304c4\u520612\u79d2\u304b\u30892\u520647\u79d2\u306b\u306a\u3063\u305f\u3002CI\u306e\u8acb\u6c42\u3092\u78ba\u8a8d\u3057\u305f\u3089\u3001\u6708\u3042\u305f\u308a\u7d04$40\u306e\u30b3\u30b9\u30c8\u524a\u6e1b\u306b\u306a\u3063\u3066\u3044\u305f\u3002\u30c1\u30fc\u30e0\u5168\u54e1\u306e\u30ed\u30fc\u30ab\u30eb\u3067\u306e<code>tsc --build<\/code>\u3082\u4f53\u611f\u3067\u901f\u304f\u306a\u3063\u305f\u3002<\/p>\n<p>\u300cCI\u304c\u9045\u304f\u3066\u56f0\u3063\u3066\u3044\u308b\u300d\u3068\u3044\u3046\u5177\u4f53\u7684\u306a\u75db\u307f\u304c\u3042\u308b\u306a\u3089\u8a66\u3059\u4fa1\u5024\u306f\u3042\u308b\u3002\u305d\u3046\u3058\u3083\u306a\u3051\u308c\u3070\u5f8c\u56de\u3057\u3067\u3044\u3044\u3002<\/p>\n<hr \/>\n<h2>\u512a\u5148\u9806\u4f4d\u306e\u8a71<\/h2>\n<p>\u5168\u90e8\u4e00\u6c17\u306b\u3084\u308b\u5fc5\u8981\u306f\u306a\u3044\u3057\u3001\u3084\u308d\u3046\u3068\u3059\u308b\u3068\u5931\u901f\u3059\u308b\u3002<\/p>\n<p>\u578b\u8ff0\u8a9e\u306e\u81ea\u52d5\u63a8\u8ad6(5.5)\u306f\u30d0\u30fc\u30b8\u30e7\u30f3\u30a2\u30c3\u30d7\u3059\u308b\u3060\u3051\u3067\u6069\u6075\u3092\u53d7\u3051\u3089\u308c\u308b\u3002\u30b3\u30fc\u30c9\u3092\u66f8\u304d\u63db\u3048\u308b\u5fc5\u8981\u304c\u306a\u3044\u3002\u307e\u305a\u30d0\u30fc\u30b8\u30e7\u30f3\u30a2\u30c3\u30d7\u3060\u3051\u3057\u3066\u3001\u65e2\u5b58\u306e\u578b\u8ff0\u8a9e\u30d8\u30eb\u30d1\u30fc\u304c\u4e0d\u8981\u306b\u306a\u3063\u3066\u3044\u306a\u3044\u304b\u78ba\u8a8d\u3059\u308b\u3053\u3068\u304b\u3089\u59cb\u3081\u308b\u3068\u3044\u3044\u3002\u524a\u9664\u3067\u304d\u305f\u3089\u5132\u3051\u3082\u306e\u3002<\/p>\n<p><code>NoInfer&lt;T&gt;<\/code>(5.4)\u306f\u30e9\u30a4\u30d6\u30e9\u30ea\u3084\u5185\u90e8API\u3092\u8a2d\u8a08\u3057\u3066\u3044\u308b\u306a\u3089\u4eca\u3059\u3050\u691c\u8a0e\u3059\u308b\u4fa1\u5024\u304c\u3042\u308b\u3002\u5b9f\u88c5\u30b3\u30b9\u30c8\u304c\u4f4e\u3044\u5272\u306b\u3001\u578b\u8a2d\u8a08\u306e\u8868\u73fe\u529b\u304c\u4e0a\u304c\u308b\u3002<\/p>\n<p><code>using<\/code>\u5ba3\u8a00(5.2)\u306f\u30ea\u30bd\u30fc\u30b9\u7ba1\u7406\u306e\u30b3\u30fc\u30c9\u304c\u3042\u308b\u5834\u6240\u304b\u3089\u6bb5\u968e\u7684\u306b\u5c0e\u5165\u3067\u304d\u308b\u3002\u6700\u521d\u306e1\u500b\u306e\u30e9\u30c3\u30d1\u30fc\u30af\u30e9\u30b9\u3092\u66f8\u3044\u3066\u307f\u308b\u3068\u3001\u4f7f\u3044\u3069\u3053\u308d\u304c\u898b\u3048\u3066\u304f\u308b\u3002<\/p>\n<p><code>--isolatedDeclarations<\/code>(5.5)\u306f\u30e2\u30ce\u30ec\u30dd\u3092\u6301\u3063\u3066\u3044\u3066CI\u304c\u9045\u3044\u306a\u3089\u691c\u8a0e\u3059\u308b\u3002\u79fb\u884c\u30b3\u30b9\u30c8\u306f\u78ba\u5b9f\u306b\u3042\u308b\u3051\u3069\u3001\u9577\u671f\u7684\u306a\u30ea\u30bf\u30fc\u30f3\u306f\u51fa\u308b\u3002<\/p>\n<p>\u6bce\u56de\u306eTypeScript\u30ea\u30ea\u30fc\u30b9\u3067\u300c\u5168\u90e8\u628a\u63e1\u3057\u306a\u304d\u3083\u300d\u3068\u3044\u3046\u30d7\u30ec\u30c3\u30b7\u30e3\u30fc\u3092\u611f\u3058\u308b\u3053\u3068\u304c\u3042\u308b\u3051\u3069\u3001\u5b9f\u969b\u306b\u672c\u756a\u3067\u5dee\u304c\u51fa\u308b\u3082\u306e\u306f\u305d\u3053\u307e\u3067\u591a\u304f\u306a\u3044\u3002\u3053\u306e4\u3064\u306f\u3001\u3046\u3061\u306e\u65e5\u5e38\u7684\u306a\u4f5c\u696d\u306e\u8cea\u3092\u5b9f\u969b\u306b\u5909\u3048\u305f\u3002\u3042\u306a\u305f\u306e\u30b3\u30fc\u30c9\u30d9\u30fc\u30b9\u3067\u540c\u3058\u306b\u306a\u308b\u304b\u3069\u3046\u304b\u306f\u308f\u304b\u3089\u306a\u3044 \u2014 \u30b9\u30bf\u30c3\u30af\u3082\u30c1\u30fc\u30e0\u30b5\u30a4\u30ba\u3082\u9055\u3046\u304b\u3089\u3002\u3067\u3082\u8a66\u3057\u3066\u307f\u308b\u4fa1\u5024\u306f\u3001\u5c11\u306a\u304f\u3068\u3082\u3042\u308b\u3002<\/p>\n<p><!-- Reviewed: 2026-03-10 | Status: ready_to_publish | Changes: removed English filler phrase (\"Right, so \u2014\") embedded in Japanese text, added personality details (\u624b\u75db\u3044\u6848\u4ef6, \u3052\u3093\u306a\u308a\u3057\u305f, CI\u306e\u9045\u3055\u306b\u6bce\u65e5\u307c\u3084\u3044\u3066\u3044\u305f), varied paragraph lengths, tightened isolatedDeclarations intro, made conclusion section less formulaic --><\/p>\n","protected":false},"excerpt":{"rendered":"<p>TypeScript 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