javascript function wait until another function to finish

Question

I have two javascript functions that are called from android  After long debug sessions finally I realized that the problem is arising from the fact that second function is getting called before first one is finished  I already searched the examples with deferred etc  but they all depends on function calls within another one    function FunctInit someVarible     someVariable is sent from android  cannot call again from getResult   init and fill screen    function getResult      also getResult need to be called from android via button   return some variables     How can I force getResult to wait FuncInit  Is there a way to achieve this via Javascript

User · Answer

Following answer can help in this and other similar situations like synchronous AJAX call -

Working example

waitForMe().then(function(intentsArr){
  console.log('Finally, I can execute!!!');
},
function(err){
  console.log('This is error message.');
})

function waitForMe(){
    // Returns promise
    console.log('Inside waitForMe');
    return new Promise(function(resolve, reject){
        if(true){ // Try changing to 'false'
            setTimeout(function(){
                console.log('waitForMe\'s function succeeded');
                resolve();
            }, 2500);
        }
        else{
            setTimeout(function(){
                console.log('waitForMe\'s else block failed');
                resolve();
            }, 2500);
        }
    });
}

User · Answer

There are several ways I can think of to do this   Use a callback    function FunctInit someVarible           init and fill screen       AndroidCallGetResult        Enables Android button       function getResult       Called from Android button only after button is enabled         return some variables      Use a Timeout  this would probably be my preference     var inited   false   function FunctInit someVarible           init and fill screen       inited   true       function getResult          if  inited                 return some variables         else              setTimeout getResult  250                Wait for the initialization to occur    var inited   false   function FunctInit someVarible           init and fill screen       inited   true       function getResult          var a   1        do   a 1          while  inited           return some variables

User · Answer

In my opinion  deferreds promises  as you have mentionned  is the way to go  rather than using timeouts   Here is an example I have just written to demonstrate how you could do it using deferreds promises   Take some time to play around with deferreds  Once you really understand them  it becomes very easy to perform asynchronous tasks   Hope this helps     function        function1   done function               function1 is done  we can now call function2         console log  function1 is done              function2   done function                  function2 is done             console log  function2 is done                              function function1        var dfrd1     Deferred        var dfrd2    Deferred         setTimeout function               doing async stuff         console log  task 1 in function1 is done             dfrd1 resolve           1000        setTimeout function               doing more async stuff         console log  task 2 in function1 is done             dfrd2 resolve           750        return   when dfrd1  dfrd2  done function            console log  both tasks in function1 are done               Both asyncs tasks are done        promise       function function2        var dfrd1     Deferred        setTimeout function               doing async stuff         console log  task 1 in function2 is done             dfrd1 resolve           2000       return dfrd1 promise

[javascript] javascript function wait until another function to finish

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