Be able to safely access props on deep objects. Demo: http://jsbin.com/beferuviqo/1/edit

safeGet.js

// Sample object
var mySampleData = {
    foo: {
        bar: [
            1,
            2,
            {
                baz: "hello",
                wut: 2,
                hi: [7, 8, 9]
            }
        ],
        size: "large",
        party: "hard",
        really: {
          yeah: ["right?", "I'm working!"]
        }
    }
};

/** 
 * This function accepts an object and a property path to ensure safe prop access
 * @function safeGet
 * @param obj {object} The object that should contain the prop
 * @param path {string} The path of properties that should access the wanted value
 * @return {*} Returns the value of the property or null if it doesn't exist
 */
function safeGet (obj, path) {
    var arr = path.split('.'), // Create array of props
        currentPos = obj, // Start at whole object
        i = 0,
        len = arr.length,
        objProp = '',
        arrIdx,
        openBracketIdx,
        closeBracketIdx;
  
    /** Loop over the given props */
    for (i; i < len; i++) {
      openBracketIdx = arr[i].indexOf('[');
      closeBracketIdx = arr[i].indexOf(']');
      
      /** Is this property a prop and array index? E.g.: prop[index] */
      if (openBracketIdx !== -1) {
        objProp = arr[i].slice(0, openBracketIdx); // Grab prop
        arrIdx = arr[i].slice(openBracketIdx + 1, closeBracketIdx); // Grab index
        
        /** Does the current prop exist on the object?
         * If not, return null.
         */
        if (!currentPos[objProp]) {
          return null;
        }
        /** Since the prop does exist, grab the index off the prop and 
         * save to current position
         */
        currentPos = currentPos[objProp][arrIdx];
        
        /** Is this the last prop on the string?
         * If yes, return the value of prop.
         */
        if (len - i === 1) {
          return currentPos;
        }
      
      } else if (currentPos[arr[i]]) { // If just a plain obj property
        currentPos = currentPos[arr[i]];
                 
        /** Is this the last prop on the string?
         * If yes, return the value of prop.
         */
        if (len - i === 1) {
          return currentPos;
        }
      
      } else { // Prop does not exist, so return null
        return null;
      }
    }
}

var negativeTest = safeGet(mySampleData, "foo.bar[1].foo.none");
console.log("This is the negative test: " + negativeTest);

var positiveTest = safeGet(mySampleData, "foo.really.yeah[1]");
console.log("This is the positive test: " + positiveTest);