Extension of a loosely typed Map<K, V> generic in TypeScript

TypedMap.ts

interface TypedMap<M extends Record<string | number | symbol, any>> extends Map<keyof M, any> {
	get: <K extends keyof M>(key: K) => M[K]
	set: <K extends keyof M>(key: K, value: M[K]) => this
	has: <K extends keyof M>(key: K) => boolean 
	delete: <K extends keyof M>(key: K) => boolean
	forEach: (callbackFn: (value: M[keyof M], key: keyof M, map: TypedMap<M>) => void, thisArg?: any) => void
 	entries: () => IterableIterator<[ keyof M, M[keyof M] ]>
	keys: () => IterableIterator<keyof M>
	values: () => IterableIterator<M[keyof M]>
	[Symbol.iterator]: () => IterableIterator<[ keyof M, M[keyof M] ]>
}

// how to use:

interface IMap {
	foo: string
	bar: number
}

const map = new Map() as TypedMap<IMap>

map.set('foo', 'a') // ok
map.set('bar', 'b') // Error: Argument of type 'string' is not assignable...

const foo = map.get('foo') // output type: string
const bar = map.get('bar') // output type: number
const baz = map.get('baz') // Error: Argument of type '"baz"' is not assignable...