//// [promiseChaining2.ts] // same example but with constraints on each type parameter class Chain2 { constructor(public value: T) { } then(cb: (x: T) => S): Chain2 { var result = cb(this.value); // should get a fresh type parameter which each then call var z = this.then(x => result).then(x => "abc").then(x => x.length); return new Chain2(result); } } //// [promiseChaining2.js] // same example but with constraints on each type parameter var Chain2 = (function () { function Chain2(value) { this.value = value; } Chain2.prototype.then = function (cb) { var result = cb(this.value); // should get a fresh type parameter which each then call var z = this.then(function (x) { return result; }).then(function (x) { return "abc"; }).then(function (x) { return x.length; }); return new Chain2(result); }; return Chain2; })();