How to return data from promise

Question

I need to get the response data out of the promise so it can be returned by the enclosing function  I know  I probably can t do it the way I ve coded it because of normal JavaScript scope  Is there any way  it can be done   The console log at  1 produces the correct data  console log  2 always produces  a    function addSiteParentId nodeId           var theParentId    a       var parentId   relationsManagerResource GetParentId nodeId                           then function response                                                              theParentId   response data                              console log theParentId        1                                 console log theParentId        2     return theParentId      Any pointers would be appreciated

User · Accepted Answer

One of the fundamental principles behind a promise is that it's handled asynchronously. This means that you cannot create a promise and then immediately use its result synchronously in your code (e.g. it's not possible to return the result of a promise from within the function that initiated the promise).

What you likely want to do instead is to return the entire promise itself. Then whatever function needs its result can call .then() on the promise, and the result will be there when the promise has been resolved.

Here is a resource from HTML5Rocks that goes over the lifecycle of a promise, and how its output is resolved asynchronously:
http://www.html5rocks.com/en/tutorials/es6/promises/

User · Answer

You have to return a promise instead of a variable  So in your function just return   return relationsManagerResource GetParentId nodeId    And later resolve the returned promise  Or you can make another deferred and resolve theParentId with it

User · Answer

I also don t like using a function to handle a property which has been resolved again and again in every controller and service  Seem I m not alone  D  Don t tried to get result with a promise as a variable  of course no way  But I found and use a solution below to access to the result as a property   Firstly  write result to a property of your service   app factory  your factory  function        var theParentIdResult   null      var factoryReturn               theParentId  theParentIdResult          addSiteParentId   addSiteParentId            return factoryReturn      function addSiteParentId nodeId                var theParentId    a            var parentId   relationsManagerResource GetParentId nodeId                then function response                                                   factoryReturn theParentIdResult   response data                   console log theParentId        1                                                         Now  we just need to ensure that method addSiteParentId always be resolved before we accessed to property theParentId  We can achieve this by using some ways    Use resolve in router method   resolve        parentId  function  your factory             your factory addSiteParentId               then in controller and other services used in your router  just call your factory theParentId to get your property  Referce here for more information  http   odetocode com blogs scott archive 2014 05 20 using-resolve-in-angularjs-routes aspx   Use run method of app to resolve your service   app run function  your factory    your factory addSiteParentId        Inject it in the first controller or services of the controller  In the controller we can call all required init services  Then all remain controllers as children of main controller can be accessed to this property normally as you want    Chose your ways depend on your context depend on scope of your variable and reading frequency of your variable

[javascript] How to return data from promise

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