Migrate To Shoehorn

迁移到 Shoehorn

为什么用 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：

• 经过训练，不去使用它
• 必须手动指定 target type
• 对故意错误的数据需要 double-as（as unknown as Type）

安装

npm i @total-typescript/shoehorn

迁移模式

只需要少数属性的大型 objects

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 } }));

何时使用哪一个

工作流

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