Angular 1.5 scope variable undefined in $http service success callback

Question

Given the following Angular 1.5 Component Controller...

'use strict'

 function MyController($http){

    //The template variable for cloning on a form
    this.myVarTemplate = {};
    //The Data I wish to send to the server
    this.myVarTemplate.data = {};
    //Other form specific / callback data
    this.myVarTemplate.meta = {};
    this.myVarArray = [];
    //A container of raw data I'm parsing for example, on whitespace bound to a text input
    this.rawInput = '';

    this.parse = function(){
        var temp = this.rawInput.split(' ');
        for( var i = 0; i < temp.length; i++){
            var container = angular.copy(this.myVarTemplate);
            container.data = temp[i];
            this.myVarArray.push(container);
        }
    }

    this.upload = function(){
        for(var i = 0; i < this.myVarArray.length; i++){
            $http({
                method: 'POST',
                url: <url here>,
                data: this.myVarArray[i]
            }).then(function(response){
                //My Success callback won't work!!!!
                //Response logs successfully, data is retrieved
                console.log(response);
                //this.myVarArray.meta is undefined??
                //console.log(this.myVarArray) is undefined
                this.myVarArray[i].meta.reply = response.data;
            }, function(message){
                //Never been an issue here
                alert('Something Bad happened? doesn't happen');
            }).finally(function(){
                //Works
                this.myVarArray[i].meta.wasSent = true;
            });
        }
    }
})

I am trying to return a batch of AJAX query results to their proper corresponding form objects. It seems as though this.myVarArray is undefined within the context of the $http service success callback. Why is this? Is this a quirk of Angular or of Javascript itself? I understand that the $http service returns a promise, but that should be resolved within the context of the callback. Why is myVarArray undefined?

Many thanks in advance for any insight.

Edited: Fixed my example code... :)

I no longer get an error. However, the response is not returned to the array object. Will post update code in a sec — NetSaber777
– NetSaber777, Commented Apr 8, 2016 at 22:46

MichaelWClark · Accepted Answer · 2016-04-08 22:33:32Z

1

this.myVarArray is an array of string based on what has been split from raw input in your parse. You are trying to assign an object property (.meta) to a string array element. You could try something along the lines of:

this.myVarObjArray;
this.rawInput = '';

this.parse = function(){
    var temp = this.rawInput.split(' ');
    var valArray = []
    for( var i = 0; i < temp.length; i++){
        valArray.push(angular.copy(temp[i]));
        this.myVarObjArray[i] = { val: valArray};
    }

}

this.upload = function(){
    angular.forEach(this.myVarObjArray, function(obj,v){
        $http({
            method: 'POST',
            url: <url here>,
            data: obj.val
        }).then(function(response){
            //My Success callback won't work!!!!
            //Response logs successfully, data is retrieved
            console.log(response);
            //this.myVarArray.meta is undefined??
            //console.log(this.myVarArray) is undefined
            obj.meta = {reply :response.data};
....
    })

Essentially your trying to assign an object property to a string array element. This won't work. My syntax might not be 100%. If you pull into a plunker i'll get a working example for you. This should get you on the right track.

answered Apr 8, 2016 at 22:33

MichaelWClark

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3 Comments

NetSaber777 Over a year ago

Awesome, thanks Michael. This in combination with @jb-nizet 's initial help seems to have me on the right track. Trying to get an example I can play with soon.

NetSaber777 Over a year ago

Got it working. Between @jbnizet and you, I also have a better understand of Angular / js. Many thanks.

NetSaber777 Over a year ago

For any future viewer, there were two issues. JB's initial response on the lifespan of iterative variables inside the loop requires the uses of forEach over for(){} in cases using promises / other async. @MichaelWClark then found I botched my response assignment back to the Controller variable.

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