Migrate to Shoehorn 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. Problems with as in tests: Trained not to use it Must manually specify target type Double-as ( as unknown as Type ) for intentionally wrong data 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 Function Use case fromPartial() Pass partial data that still type-checks fromAny() Pass intentionally wrong data (keeps autocomplete) fromExact() Force full object (swap with fromPartial later) Workflow Gather requirements - ask user: What test files have as assertions causing problems? Are they dealing with large objects where only some properties matter? Do they need to pass intentionally wrong data for error testing? Install and migrate : Install: npm i @total-typescript/shoehorn Find test files with as assertions: grep -r " as [A-Z]" --include=".test.ts" --include=".spec.ts" Replace as Type with fromPartial() Replace as unknown as Type with fromAny() Add imports from @total-typescript/shoehorn Run type check to verify