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/shoehornMigration 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 purposeAfter:
import { fromAny } from "@total-typescript/shoehorn";
getUser(fromAny({ body: { id: 123 } }));When to use each
| Function | Use 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
- Gather requirements — 询问用户：
- 哪些 test files 中的
asassertions 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？
- Install and migrate：
- [ ] Install:
npm i @total-typescript/shoehorn - [ ] 查找 test files 中的
asassertions: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
