Javascript property enumeration

answer.md

Q: Why don't have to write conditional statement to determine whether input is object or array? A: because Object.keys behave similarly when input is input or object, It returns an array of index when input is an array. See below example from MDN doc.

var arr = ['a', 'b', 'c']; console.log(Object.keys(arr)); // console: ['0', '1', '2']

test.js

  function deepEach(obj, fn){
    keys = Object.keys(obj);
    keys.forEach(function(key){
      if(typeof obj[key] === 'object')
      deepEach(obj[key], fn);
      else
      fn(obj[key]);  
    });
  }
  deepEach(['H', {arr:['e'], str: 'l'}, 'l', [{letter: 'o'}]],console.log.bind(console));