CODEWITHSUNDEEP
javascriptnode.jsfirebasefor-looppromise
Nathan Liu
Nathan Liu

Reputation: 284

Promise in for loop in promise chain

I have a bit of a messy problem I can't find a proper answer for. It's in firebase which doesn't support await and async.

At the moment, it works, but only runs once and doesn't loop.

return foo.bar(query);})
        .then((result) => {

            if (result == '0') {
               //do stuff
            } 


            else {
                var i;
                for(i = 0; i <= result; i++) {
                    return foo.bar(secondQuery);})
                    .then((secondResult) => {
                        //do other stuff                


                    })
                }

            }

        })

Upvotes: 3

Views: 3335

Answers (1)

Hyyan Abo Fakher
Hyyan Abo Fakher

Reputation: 3537

You can use Promise.all

The Promise.all(iterable) method returns a single Promise that resolves when all of the promises in the iterable argument have resolved or when the iterable argument contains no promises. It rejects with the reason of the first promise that rejects.

return foo.bar(query).then(result => {

  if (result == '0') {
    //do stuff
  } else {

    var i;
    var all = [];
    for (i = 0; i <= result; i++) {
      var p = foo.bar(secondQuery).then((secondResult) => {
        //do other stuff                
      });

      all.push(p)
    }

    return Promise.all(all);
  }

});

Upvotes: 3

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