Getting JavaScript object key list

Question

I have a JavaScript object like

var obj = {
   key1: \'value1\',
   key2: \'value2\',
   key3: \'value3\',
   key4: \'value4\'
}

How can I

Answer 1

If you decide to use Underscore.js you better do

var obj = {
    key1: 'value1',
    key2: 'value2',
    key3: 'value3',
    key4: 'value4'
}

var keys = [];
_.each( obj, function( val, key ) {
    keys.push(key);
});
console.log(keys.lenth, keys);