How to convert a javascript string to reference an object property? [duplicate]

This question already has an answer here:

• Dynamically access object property using variable 3 answers

I have a custom object with a bunch of array properties.

function Location (name, displayName){
  this.name = name,
  this.displayName = displayName,
  Location.objects.push(this);                           
}
Location.objects = [];

//Initialize Farm
var farm = new Location();

farm.scenes = [
  "content 0",
  "content 1",
  "Content 2"
];

Using JQuery, I am grabbing an attribute from the DOM that I need to use to call values from within the object.

$('button').click(function(){
      var location = $(this).attr('id'); //in this case, the id is 'farm'
      mainLoop(location);
});

function mainLoop(location){
  console.log(farm.scenes.length);// returns '3' as desired    
  console.log(location.scenes.length);//returns undefined because location is a string. I need this to work.
  console.log(location[scenes][length]); //same problem
}

The only solution I've found this far is to use eval(), but I cannot do that because this data could be manipulated by the end user.

function mainLoop(location){
  location = eval(location); 
  console.log(location.scenes.length);//returns 3 as desired
}

I need an alternative way to somehow take this string and turn it into an object property reference. In this case, I am working with a limited amount of results, so I could potentially map a set of strings to identifiers, but I feel like there's probably a more elegant solution for this, though I can't figure out what question I should be typing into stackoverflow.