//// [genericArray1.ts] /* var n: number[]; interface Array { map(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; } interface String{ length: number; } */ var lengths = ["a", "b", "c"].map(x => x.length); //// [genericArray1.js] /* var n: number[]; interface Array { map(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[]; } interface String{ length: number; } */ var lengths = ["a", "b", "c"].map(function (x) { return x.length; }); //// [genericArray1.d.ts] declare var lengths: number[];