Use an intersection type when need to extend a type and the extends keyword when extending interfaces.

intersection-vs-extends.ts

// Create intersection type to "extend" types by combining them

type BaseType = {
    readonly id: string
}

const intersection: BaseType & {  kind: string } = {
    id: ‘123’,
    kind: ‘intersection’
}

// Extend an interface to add additional properties

interface BaseInterface {
    readonly id: string,
}

interface extended extends BaseInterface {
    kind: string
}

const extended: extended = {
    id: ‘123’,
    kind: ‘intersection’
}