MapSpec

Premium

Updated on Apr 2, 2026

Defines a mapping specification object that maps target object properties to source extraction rules.

Each property in the target type can be mapped using either a property path string or a function that extracts the value from the source object. This allows flexible transformation of data from one structure to another.

typescript

interface Person { name: string; age: number; }
interface User { id: string; fullName: string; }

const mapping: MapSpec<User, Person> = {
  name: 'fullName',           // Direct property mapping
  age: (user) => user.age || 0 // Function-based mapping with default
};