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migrate-to-shoehorn

Testing & Quality
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将测试文件从 `as` 类型断言迁移到 @total-typescript/shoehorn。适用于用户提到 shoehorn、想替换测试中的 `as`，或需要局部测试数据时。

QUICK START

How to use this skill

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Source SKILL.md: https://github.com/vinvcn/mattpocock-skills-zh-CN/blob/HEAD/skills/misc/migrate-to-shoehorn/SKILL.md

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Migrate to Shoehorn

Why shoehorn?

shoehorn 允许你在 tests 中传入 partial data，同时保持 TypeScript 满意。它用 type-safe alternatives 替换 as assertions。

只用于 test code。 永远不要在 production code 中使用 shoehorn。

Tests 中 as 的问题：

  • 会训练人忽略类型安全
  • 必须手动指定 target type
  • 对故意错误的数据需要 double-as（as unknown as Type）

Install

npm i @total-typescript/shoehorn

Migration patterns

Large objects with few needed properties

Before:

type Request = {
  body: { id: string };
  headers: Record<string, string>;
  cookies: Record<string, string>;
  // ...20 more properties
};

it("gets user by id", () => {
  // Only care about body.id but must fake entire Request
  getUser({
    body: { id: "123" },
    headers: {},
    cookies: {},
    // ...fake all 20 properties
  });
});

After:

import { fromPartial } from "@total-typescript/shoehorn";

it("gets user by id", () => {
  getUser(
    fromPartial({
      body: { id: "123" },
    }),
  );
});

as Type → fromPartial()

Before:

getUser({ body: { id: "123" } } as Request);

After:

import { fromPartial } from "@total-typescript/shoehorn";

getUser(fromPartial({ body: { id: "123" } }));

as unknown as Type → fromAny()

Before:

getUser({ body: { id: 123 } } as unknown as Request); // wrong type on purpose

After:

import { fromAny } from "@total-typescript/shoehorn";

getUser(fromAny({ body: { id: 123 } }));

When to use each

FunctionUse case
fromPartial()传入仍能 type-check 的 partial data
fromAny()传入故意错误的数据（保留 autocomplete）
fromExact()强制 full object（之后可换成 fromPartial）

Workflow

  1. Gather requirements — 询问用户：

    • 哪些 test files 中的 as assertions 造成问题？
    • 是否在处理大型 objects，但只关心部分 properties？
    • 是否需要传入故意错误的数据来测试 error paths？

  2. Install and migrate：

    • Install: npm i @total-typescript/shoehorn
    • 查找 test files 中的 as assertions: grep -r " as [A-Z]" --include="*.test.ts" --include="*.spec.ts"
    • 用 fromPartial() 替换 as Type
    • 用 fromAny() 替换 as unknown as Type
    • 添加来自 @total-typescript/shoehorn 的 imports
    • 运行 type check 验证