Handling Promises in Angular 1 App using Typescript ES6/2015

Question

Handling Promises in Angular 1 App using Typescript ES6/2015

Currently, I am working on an Angular 1.5 application that utilizes Typescript. My main concern is finding the most efficient way to handle ng.IPromise compared to Promise (ES6 promise). Personally, I would prefer to solely deal with the ES6 Promise type. Is there a sleek method to override all angular-js and angular-material interfaces to align with ES6 promises?

These are the options I have considered:

Utilize some d.ts sorcery to achieve this goal (is it feasible?)
Manually convert to ES6 Promise across the board (effective, but not very intuitive)
Get involved in open source, modify the typings for ng and ng material, and adjust their return types to ES6 Promise (this may be the best solution, although it could be time-consuming)

Just to clarify:

The underlying Promise implementation being used by the angular application remains as $q (even though I am also implementing angular-bluebird-promises). My focus is solely on simplifying/streamlining the Typescript interfaces being utilized.

angularjs typescript angular-promise es6-promise

Answer 1

Answer №1

There are numerous compelling reasons why maintaining two distinct interfaces is crucial.

The disparities between $q promises and other implementations are foundational. The $q chain can operate synchronously and execute on digest, a characteristic not shared by other promises such as the native Promise.

In a TS/ES6 application where both native promises and $q promises coexist, it may seem logical to unify them under a common denominator like IPromise (without the ng prefix). However, this approach lacks practicality. Mistakenly using a native promise in code expecting a $q promise (or vice versa) is highly undesirable, and using a shared IPromise will not prevent this error from occurring due to TypeScripts' constraints.

If an Angular promise is intended for exportation to non-Angular code usage, converting it to a Promise, as proposed in another response, is preferable.

In a non-Angular setting,

let exportedPromise = getResolvedPromise();
...
exportedPromise.then(...);

this code snippet

function getResolvedPromise() {
  return Promise.resolve($q.resolve());
};

will trigger the then callback on the next tick. On the contrary,

function getResolvedPromise() {
  return $q.resolve();
};

will delay the chain until the following root scope digest, despite having chained the then method to the resolved promise.

Although unrelated to TypeScript, this query exemplifies the significance of always distinguishing between using a $q promise versus a native promise.

Answer 2

There are numerous compelling reasons why maintaining two distinct interfaces is crucial.

The disparities between $q promises and other implementations are foundational. The $q chain can operate synchronously and execute on digest, a characteristic not shared by other promises such as the native Promise.

In a TS/ES6 application where both native promises and $q promises coexist, it may seem logical to unify them under a common denominator like IPromise (without the ng prefix). However, this approach lacks practicality. Mistakenly using a native promise in code expecting a $q promise (or vice versa) is highly undesirable, and using a shared IPromise will not prevent this error from occurring due to TypeScripts' constraints.

If an Angular promise is intended for exportation to non-Angular code usage, converting it to a Promise, as proposed in another response, is preferable.

In a non-Angular setting,

let exportedPromise = getResolvedPromise();
...
exportedPromise.then(...);

this code snippet

function getResolvedPromise() {
  return Promise.resolve($q.resolve());
};

will trigger the then callback on the next tick. On the contrary,

function getResolvedPromise() {
  return $q.resolve();
};

will delay the chain until the following root scope digest, despite having chained the then method to the resolved promise.

Although unrelated to TypeScript, this query exemplifies the significance of always distinguishing between using a $q promise versus a native promise.

Answer 3

Answer №2

Is there a more refined approach to integrating es6 promises into both angular-js and angular-material interfaces?

We have adopted the use of IPromise throughout our codebase. Replacing IPromise with Promise is not straightforward due to differences in implementation. One workaround could be using Promise.resolve(someIPromise), but this might not seamlessly integrate with angular.

Answer 4

Is there a more refined approach to integrating es6 promises into both angular-js and angular-material interfaces?

We have adopted the use of IPromise throughout our codebase. Replacing IPromise with Promise is not straightforward due to differences in implementation. One workaround could be using Promise.resolve(someIPromise), but this might not seamlessly integrate with angular.

Handling Promises in Angular 1 App using Typescript ES6/2015

Answer №1

Answer №2

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