Search an object inside an Array of objects using a key

in-arr-object.js

/**
 * Searches object in Array by key
 * 
 * Usage:
 * 
 * List should be an Array like this
 * var foo = {};
 * var list = [
 *  { name: {} }, { name: foo }, { name: {} }
 * ];
 * 
 * contains('name', foo, list);   // Returns 1
 * contains('name', {}, list);   // Returns -1
 * 
 * 
 * Return the index if object is found, else -1
 * 
 * @param {String} key
 * @param {Object} obj
 * @param {Array} list
 * @returns {Number}
 */
function contains(key, obj, list) {
  for (var i = 0, len = list.length; i < len; i += 1) {
    if (list[i][key] === obj) return i;
  }

  return -1;
}