What's wrong with this async function?

Question

async lsEntered(){ if(this.service.wd == '') { await basic((this.service.wd)); } else { await basic(('/'+this.service.wd)); } this.files = await JSON.parse(localStorage.getItem('FILENAMES')); var filesList = document.getElementById(this.trackLine.toString()); var li; for (var i = 0; i < this.files.length; i++) { li = document.createElement('li'); li.appendChild(document.createTextNode(this.files[i].name)); filesList.appendChild(li); } localStorage.clear(); }

I want to wait until basic is finished and JSON.parse finishes before displaying the values in the DOM. I'm getting the values of the previous call every time which is tell me the async is no working. To be fair I don't have tons of TS experience.

Edit: This is basic I was hoping not to have to deal with it as it's a javascript function and fragily integrated into this app.

var basic = function (path) { var ACCESS_TOKEN = ''; var dbx = new Dropbox({ accessToken: ACCESS_TOKEN }); dbx.filesListFolder({ path: path }) .then(function (response) { localStorage.setItem('FILENAMES',JSON.stringify(response.entries)); console.log(response); }) .catch(function (error) { console.error(error); }); return false; }

You might want to invalidate that access token, now that everybody can see it on the edit history — MinusFour
– MinusFour, Commented Aug 24, 2017 at 2:15
JSON.parse does not return a promise, so you should omit the await there — Bergi
– Bergi, Commented Aug 24, 2017 at 2:16
Instead of storing the result in the localstorage, you should resolve the promise with it. That would make basic much more flexible to use. — Bergi
– Bergi, Commented Aug 24, 2017 at 2:18

iTR · Accepted Answer · 2017-08-24 02:21:48Z

3

let myPromise = new Promise((resolve, reject) => { // Work you want to execute resolve("I am done"); }); myPromise.then((successMessage) => { // successMessage is whatever we passed in the resolve(...) function above. console.log("Yay! " + successMessage); });

edited Aug 24, 2017 at 2:21

answered Aug 24, 2017 at 2:09

iTR

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3 Comments

Zachscs Over a year ago

Where and how do I use promise? I'm new to this game.

Zachscs Over a year ago

Pretty helpful but I think I need to divide the code into three parts. How can I add another myPromise.then it's shooting compile errors when I try to add a third.

iTR Over a year ago

Try create an array of promises you use promise.all(). You'll find in this link developer.mozilla.org/en/docs/Web/JavaScript/Reference/…

Felix Kling · Accepted Answer · 2017-08-24 02:17:27Z

You can only await promises¹ and basic is not returning a promise. You need to do

return dbx.filesListfolder(...)...

Also consider what Bergi said in their comment.

1: Actually, you can await any value, but there is no point in awaiting something that is not a promise. By not returning the promise from basic, lsEntered won't wait for the local storage to be set.

Do I need to declare this return of dbx.filesListFolder as a promise somewhere?
I spent 3 hours trying to work with the typings and decided on doing this instead :(

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