Method map

src/vs/base/common/event.ts:550–550

(fn: (i: T) => O)

	export interface IChainableSythensis<T> {
		map<O>(fn: (i: T) => O): IChainableSythensis<O>;
		forEach(fn: (i: T) => void): IChainableSythensis<T>;
		filter<R extends T>(fn: (e: T) => e is R): IChainableSythensis<R>;
		filter(fn: (e: T) => boolean): IChainableSythensis<T>;