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1. #Visual studio 2015 intellisense javascript async await how to#
2. #Visual studio 2015 intellisense javascript async await code#

It’s all contained in tslib.js, single small file (about 200 lines of JS) that defines all helper functions TypeScript can emit. Microsoft maintains tslib, the runtime helpers library for TypeScript apps. Use TsLib.js to define the magic helper functions once. Instead of having TypeScript compiler generate that in each file, we’re just going to define those magic helper functions once. And that’s because we just told TypeScript to skip generating the _awaiter helper function. Except if you run it, you’ll get an error saying _awaiter is undefined. Instead, you’ll notice your async functions are compiled down to something like this:

#Visual studio 2015 intellisense javascript async await code#

Now if we compile our app, you’ll notice the transpiled UsersController.js (and your code files that use async functions) no longer has all the magic transpiler stuff.

You can see we’ve set noEmitHelpers to true in line 8. In my tsconfig.json file, I add the flag: This will isntruct TypeScript not to emit any of its helpers: not for async, not for generators, not for class inheritance, …nuttin’. The TypeScript 2.1+ compiler supports the noEmitHelpers flag. We can do just that, explained in steps 3 and 4 below. Ideally, we’d just generate the magic once, and have all our async functions reuse it. Love the magic, but hate the duplication we’re generating this magic for every TS file that uses async functions. Yikes! Sure, this is how the TypeScript compiler is working its magic: simulating async/await on old platforms going back to IE8 (and earlier?). If you look at the transpiled javascript, you’ll see that TypeScript is generating 2 big helper functions at the top of every file that uses an async function: That’s actually enough to start using async/await against Promise-based code, such as ng.IPromise:Ĭool. This kills two birds with one stone: we now have a Promise polyfill, and when these promises resolve, the scope will automatically be applied. Fortunately, we can just use Angular’s $q object as the Promise, as it’s A+ compatible with the Promise standard. Since older browsers may not have a global Promise object, we need to drop in a polyfill. Getting this to work with Angular is pretty simple, requiring only a single step.

#Visual studio 2015 intellisense javascript async await how to#

I didn’t find any examples online how to do this, so I did some experimenting and figured it out.įor the uninitiated, async/await is a big improvement on writing clean async code: I wanted to use the sexy new async/await functionality in my Angular code. I’m using Angular 1.x for many of my apps. TypeScript will compile it down to something all browsers can run. With TypeScript 2.1+, you can start using the awesome new async/await functionality today, even if your users are running old browsers. Summary: How to use TypeScript async/await with AngularJS 1.x apps, compiling down to ES5 browsers.