get-if-usage.js

var obj = {a: {b: 1}};
getIf(obj, 'a');                           // => {b: 1}
getIf(obj, 'absentProp');                  // => undefined
getIf(obj, 'a', 'b');                      // => 1
getIf(obj, 'a', 'b', 'absentNestedProp');  // => undefined

get-if.js

// Get nested property of an object without risking
// "TypeError: Cannot read property '[...]' of undefined"
// errors. Depends on Lo-Dash or Underscore.
function getIf(maybeObj) {
  var props = _.rest(arguments);
  return getIf1(maybeObj, props);
}

// Helper function that does the heavy lifting for `getIf`
function getIf1(maybeObj, props) {
  if (_.isEmpty(props)) return maybeObj;
  if (!_.isObject(maybeObj)) return undefined;
  return getIf1(maybeObj[_.first(props)], _.rest(props));
}