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// 场景 1：拼写错误
const u = { name: "a" };
u.nmae;
// ❌ TS2339: Property 'nmae' does not exist on type '{ name: string; }'.
//    Did you mean 'name'?          ← TS 会给建议，注意看 🔥

// 场景 2：联合类型上访问成员
declare const v: string | number;
v.toUpperCase();
// ❌ TS2339: Property 'toUpperCase' does not exist on type 'string | number'.
//    Property 'toUpperCase' does not exist on type 'number'.    ← 指出哪个成员没有
// 修法：先收窄

// 场景 3：只读数组上调可变方法
declare const ro: readonly string[];
ro.push("x");
// ❌ TS2339: Property 'push' does not exist on type 'readonly string[]'.

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error TS2304: Cannot find name 'process'.
error TS2304: Cannot find name 'Buffer'.
error TS2304: Cannot find name 'describe'.

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// 修法
{ "compilerOptions": { "types": ["node"] } }          // Node 全局
{ "compilerOptions": { "types": ["node", "vitest/globals"] } }  // 测试全局

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function f(u: unknown) {
  return u.name;
  //     ~ ❌ TS18046: 'u' is of type 'unknown'.
}

// ✅ 用守卫收窄
function g(u: unknown) {
  if (typeof u === "object" && u !== null && "name" in u) {
    return (u as { name: unknown }).name;
  }
  return undefined;
}

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error TS2769: No overload matches this call.
  Overload 1 of 2, '(input: string): string[]', gave the following error.
    Argument of type 'boolean' is not assignable to parameter of type 'string'.
  Overload 2 of 2, '(input: number): number[]', gave the following error.
    Argument of type 'boolean' is not assignable to parameter of type 'number'.
  ← TS 逐个重载告诉你为什么不行，直接看每个分支的原因

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# 1. 模块解析到底试了哪些路径？
npx tsc --noEmit --traceResolution 2>&1 | grep -A10 "my-module"

# 2. 该文件为什么被/没被包含？
npx tsc --noEmit --explainFiles | head -50

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// 🛑 无限递归（编译器无法判定终止）
type Infinite<T> = { [K in keyof T]: Infinite<T[K]> }[keyof T];

// ✅ 加深度限制
type Prev = [never, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
type SafeDeep<T, D extends number = 5> = D extends 0
  ? T
  : { [K in keyof T]: SafeDeep<T[K], Prev[D]> };

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{ "compilerOptions": { "ignoreDeprecations": "6.0" } }

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# 每个文件为什么被包含进编译
npx tsc --noEmit --explainFiles

# 模块解析全过程（每个 import 试了哪些路径）
npx tsc --noEmit --traceResolution

# 实际参与编译的文件列表
npx tsc --noEmit --listFiles

# 只看文件列表，不编译
npx tsc --listFilesOnly

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src/index.ts
  Matched by include pattern 'src/**/*.ts' in 'tsconfig.json'
node_modules/@types/node/index.d.ts
  Entry point for implicit type library 'node'

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# 各阶段耗时 + 类型/实例化计数
npx tsc --noEmit --extendedDiagnostics

# 详细统计
npx tsc --noEmit --diagnostics

# 生成 Chrome Trace 剖析
npx tsc --noEmit --generateTrace ./trace

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// .vscode/settings.json
{ "typescript.tsdk": "node_modules/typescript/lib" }