Javascript: Function - is_empty(obj)

gistfile1.js

function is_empty(obj) {
  "use strict";
  // Assume if it has a length property with a non-zero value
  // that that property is correct.
  if (obj.length && obj.length > 0){ return false; }
  if (obj.length && obj.length === 0){return true; }

  for (var key in obj) {
    if (Object.prototype.hasOwnProperty.call(obj, key)) { return false; }
  }

  return true;
}

// Examples
console.log(
    is_empty(""), // True
    is_empty([]), // True
    is_empty({}), // True
    is_empty({length: 0, custom_property: []}), // True

    is_empty("Hello"), // False
    is_empty([1,2,3]), // False
    is_empty({test: 1}), // False
    is_empty({length: 3, custom_property: [1,2,3]}) // False
);