Promises act odd when debugging in chrome

[RWOverdijk]

When enabling Debug in chrome (simulator), using promises acts up for me.

var foo = {
  bar () {
    this.getLocation().then((loc) => {
      console.log(loc);
    });
  },

  getLocation () {
    var p = new Promise((resolve, reject) => {
      navigator.geolocation.getCurrentPosition(position => {
        console.log('going to resolve');
        resolve(position);
      }, error => {
        console.log('going to reject');
        reject(error);
      }, {
        enableHighAccuracy: false,
        timeout           : 20000,
        maximumAge        : 15000
      });
    });

    p.then(position => {
      console.log('called in here');
      return position;
    });

    return p;
  },
};

foo.bar();

Sometimes (when it has to look up the position because timeout has expired) I’m getting "going to resolve” logged but nothing else. No “called in here” and no loc in the method I’m calling this from.

[brentvatne]

This actually looks like a dup of #2603 but with more information :) So let's keep this one open.

[mattdenner]

We've been seeing this issue recently too and (a very preliminary) investigation seems to suggest that it is to do with core-js attempting to detect the behaviour of Promise. Specifically our use of babel pulls in this code and triggers the check on this line in core-js, setting works to false.

In our case changing our webpack use of babel to not have optional: ["runtime"] and the app ran without need us to click on the simulator. Our app then breaks later which we need to look at!

I don't know if that's any help and, as I said, it's a very preliminary investigation.

[mkonicek]

Hi there! This issue is being closed because it has been inactive for a while.

But don't worry, it will live on with ProductPains! Check out its new home: https://productpains.com/post/react-native/promises-act-odd-when-debugging-in-chrome

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