Migrate To Shoehorn

Migrate To Shoehorn

Migrate test files from as type assertions to @total-typescript/shoehorn for type-safe partial test data.

Why shoehorn?

shoehorn lets you pass partial data in tests while keeping TypeScript happy. It replaces as assertions with type-safe alternatives.

Test code only. Never use shoehorn in production code.

Migration patterns

• Large objects with few needed properties: as Type -> fromPartial()
• Intentionally wrong types: as unknown as Type -> fromAny()

Install

npm install @total-typescript/shoehorn

Common Pitfalls

• Shoehorn in production code: Never use shoehorn (fromPartial, fromAny) in production code. It is for test files only.
• Not installing the package first: Run npm install @total-typescript/shoehorn before attempting migration.
• fromAny where fromPartial would work: Use fromPartial when you have a valid partial object, fromAny only when intentionally providing wrong types.

Code Examples

// BEFORE: Using as assertions
type Request = {
  body: { id: string };
  headers: Record<string, string>;
  cookies: Record<string, string>;
};

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

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

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

// Intentionally wrong types
// BEFORE:
getUser({ body: { id: 123 } } as unknown as Request);

// AFTER:
import { fromAny } from "@total-typescript/shoehorn";
getUser(fromAny({ body: { id: 123 } }));

Verification Checklist

• @total-typescript/shoehorn installed (npm)
• All as Type assertions in tests migrated to fromPartial()
• All as unknown as Type migrated to fromAny()
• Production code checked for shoehorn usage (should be none)
• Tests still passing after migration