An Alternative To "For Loop" With Locker Service Enabled

Question

I have yet another Locker Service question. I have built a number of Lightning components over the last few months, and they all work great, but when I enabled Locker Service I noticed that places where I use a For Loop, the components fail.

The following has a Map<String, String> returned, and it works great when Locker Service is not enabled.

 doInit : function(component, event, helper) {
    var action = component.get("c.findAll"); 
    var theAmens = component.get("v.AmenityList");

    action.setParams({ 'amenityTypes' : theAmens });
    action.setCallback(this, function(response) {
        var state = response.getState();
        if (state === "SUCCESS") {                
            var spcs = [];
            var theSpaces = response.getReturnValue();
            console.log("the Spaces " + theSpaces);
            for ( key in theSpaces ) {
                spcs.push({value:theSpaces[key], key:key});
            }
            component.set("v.spaces", spcs);
        }  
  });           
  $A.enqueueAction(action);
} 

Has anyone else had a similar problem, and what is the solution?

Answer 1

From my observations, Locker Service adds getter/setter functions to your objects (according to what level of access you should have to them i.e. no setter if you shouldn't be able to write the field). So, the problem in your code might be that you're picking up those new functions in your for loop.

You could try this:

for (var key in theSpaces ) {
  var value = theSpaces[key];
  if(typeof value != 'function') {
    spcs.push({value:value, key:key});
  }
}

If that's not it, could you be more specific about any error messages that you're getting?