These codes:
getItems = function () { var deferred = $q.defer(); try { . . . deferred.resolve(itemsToBeReturned); } catch(error) { . . . deferred.reject(error); } return deferred.promise; };are converted into:
getItems() { return new Promise((resolve, reject) => { try { . . . resolve(itemsToBeReturned); } catch(error) { . . . reject(error); } }); };The consuming function can remain the same:
this.getItems() .then((items) => { // success . . . }) .catch(error => { // error . . . });
The new JavaScript Promise also allowed the promises returned to be chained:
getItems() { return new Promise((resolve, reject) => { this.doSomething() .then((rs) => { . . . return Promise.resolve(123); }) .then((rs) => { . . . return 456; // this returns a promise as well }) .then((rs) => { . . . resolve(result); }) .catch(error => reject(error)); }); };
Reference:
Promise - TypeScript Deep Dive
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