Merge two types into a new type. Keys of the second type overrides keys of the first type.
For example
type foo = {
name: string;
age: string;
}
type coo = {
age: number;
sex: string
}
type Result = Merge<foo,coo>; // expected to be {name: string, age: number, sex: string}
PropertyKeyis the special key for Record type: https://www.typescriptlang.org/docs/handbook/2/mapped-types.html
/* _____________ Your Code Here _____________ */
type Merge<F extends Record<PropertyKey, any>, S extends Record<PropertyKey, any>> = {
[K in keyof F | keyof S]: K extends keyof S ? S[K] : F[K]
}
/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'
type Foo = {
a: number
b: string
}
type Bar = {
b: number
c: boolean
}
type cases = [
Expect<Equal<Merge<Foo, Bar>, {
a: number
b: number
c: boolean
}>>,
]
Without PropertyKey:
/* _____________ Your Code Here _____________ */
type Merge<F, S> = {
[K in keyof F | keyof S]: K extends keyof S ? S[K] : K extends keyof F ? F[K]: never
}
/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'
type Foo = {
a: number
b: string
}
type Bar = {
b: number
c: boolean
}
type cases = [
Expect<Equal<Merge<Foo, Bar>, {
a: number
b: number
c: boolean
}>>,
]标签：Typescript,string,_____________,36,number,Merge,keyof,type From： https://www.cnblogs.com/Answer1215/p/16727144.html