Wait for all promises to resolve

Question

So I have a situation where I have multiple promise chains of an unknown length  I want some action to run when all the CHAINS have been processed  Is that even possible  Here is an example   app controller  MainCtrl   function  scope   q   timeout        var one    q defer        var two    q defer        var three    q defer         var all    q all  one promise  two promise  three promise        all then allSuccess        function success data            console log data           return data    Chained              function allSuccess            console log  ALL PROMISES RESOLVED              one promise then success  then success       two promise then success       three promise then success  then success  then success         timeout function              one resolve  one done           Math random     1000         timeout function              two resolve  two done           Math random     1000         timeout function              three resolve  three done           Math random     1000         In this example  I set up a  q all   for promises one  two  and three which will get resolved at some random time  I then add promises onto the ends of one and three  I want the all to resolve when all the chains have been resolved  Here is the output when I run this code   one done  one doneChained two done three done ALL PROMISES RESOLVED three doneChained three doneChainedChained    Is there a way to wait for the chains to resolve

User · Answer

Recently had this problem but with unkown number of promises Solved using jQuery map     function methodThatChainsPromises args           var args                myArg1              myArg2              myArg3                 var deferred    q defer        var chain   args map methodThatTakeArgAndReturnsPromise         q all chain       then function               log debug  All promises have been resolved             deferred resolve                catch function               log debug  One or more promises failed             deferred reject                 return deferred promise

User · Answer

I want the all to resolve when all the chains have been resolved    Sure  then just pass the promise of each chain into the all   instead of the initial promises    q all  one promise  two promise  three promise   then function         console log  ALL INITIAL PROMISES RESOLVED         var onechain     one promise then success  then success       twochain     two promise then success       threechain   three promise then success  then success  then success     q all  onechain  twochain  threechain   then function         console log  ALL PROMISES RESOLVED

User · Answer

You can use  await  in an  async function    app controller  MainCtrl   async function  scope   q   timeout            var all   await  q all  one promise  two promise  three promise               NOTE  I m not 100  sure you can call an async function from a non-async function and have the right results   That said this wouldn t ever be used on a website  But for load-testing integration test   maybe   Example code    x000D   x000D  async function waitForIt printMe    x000D    console log printMe   x000D    console log       await req     x000D    console log  Legendary    x000D    x000D   x000D  function req     x000D     x000D    var promise   new Promise resolve   gt    x000D      setTimeout      gt    x000D        resolve  DARY     x000D         2000   x000D       x000D        x000D   x000D      return promise  x000D    x000D   x000D  waitForIt  Legen-Wait For It    x000D   x000D   x000D

User · Answer

The accepted answer is correct  I would like to provide an example to elaborate it a bit to those who aren t familiar with promise   Example   In my example  I need to replace the src attributes of img tags with different mirror urls if available before rendering the content   var img tags   content querySelectorAll  img     function checkMirrorAvailability url            blah blah       return promise     function changeSrc success  y  response        if  success     true            img tags y  setAttribute  src   response mirror url              else           console log  No mirrors for      img tags y  getAttribute  src              var promise array        for  var y   0  y  lt  img tags length  y          var img src   img tags y  getAttribute  src         promise array push          checkMirrorAvailability img src           then                  a callback function only accept ONE argument                  Here  we use    bind  to pass additional arguments to the                callback function  changeSrc                   successCallback             changeSrc bind null  true  y                  errorCallback             changeSrc bind null  false  y                       q all promise array   then      function             console log  all promises have returned with either success or failure             render content                We don t need an errorCallback function here  because above we handled        all errors       Explanation   From AngularJS docs   The then method      then successCallback  errorCallback  notifyCallback      regardless of when the promise was or will be resolved or rejected  then calls   one of the success or error callbacks asynchronously as soon as the   result is available  The callbacks are called with a single   argument  the result or rejection reason     q all promises      Combines multiple promises into a single promise that is resolved when   all of the input promises are resolved    The promises param can be an array of promises   About bind    More info here  https   developer mozilla org en-US docs Web JavaScript Reference Global Objects Function bind

User · Answer

There is a way   q all      You can check the below stuffs   http   jsfiddle net ThomasBurleson QqKuk   http   denisonluz com blog index php 2013 10 06 angularjs-returning-multiple-promises-at-once-with-q-all

[angularjs] Wait for all promises to resolve

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