I'm trying to access the index key of a hash object via the aura expression, but it seems to return nothing/undefined. The index key was manually set via helpers through Array#Reduce.

I know I can get the index while doing an aura:iteration, but I'm dealing with a 2 dimensional array (e.g. [[object, object], [object, object]].

Below is an example:


initializeComponent: function(component, event, helper){
    var array = component.get('v.myList');
    var twoDimensionalArray = helper.createTwoDimensionArrray(array);
    //this helper function is reducing the array via Array#Reduce.

    component.set('v.newList', twoDimensionalArray);

cmp file:


  <aura:attribute name="myList" type="List[]" access="global" />
  <aura:attribute name="newList" type="List[]" access="private" />

  <aura:iteration items="{!v.newList}" var="list">
     <aura:renderIf isTrue="{!list.completed != 'true'}" >
       <aura:iteration items={!list.todos} var="todo">
          {!todo.index} : {!todo.name}


I feel like the data is being mutated by Lightning and Aura, is there a better way to do this? Am I missing something?

  • How confident are you that the array is actually populated ? Aug 15 '16 at 21:49
  • @CloudHugger pretty confident since {!todo.name} is being printed out on the page. I did find a solution for this. I created a new context of each object as I iterate over each object. After I have set the attribute to the component, it now prints the index.
    – kev_panda
    Aug 15 '16 at 23:12

I had a workaround which was to return a new hash object for each element in the array as I iterate and reduce the data. I believe because the attributes are coming from the parent, it's making it immutable. Which I personally think is great.

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