How to iterate over a JavaScript object?

Question

I have an object in JavaScript:

{
    abc: \'...\',
    bca: \'...\',
    zzz: \'...\',
    xxx: \'...\',
    ccc: \'...\',
    // ...
}

I

Answer 1

If you wanted to iterate the whole object at once you could use for in loop:

for (var i in obj) {
  ...
}

But if you want to divide the object into parts in fact you cannot. There's no guarantee that properties in the object are in any specified order. Therefore, I can think of two solutions.

First of them is to "remove" already read properties:

var i = 0;
for (var key in obj) {
    console.log(obj[key]);
    delete obj[key];
    if ( ++i > 300) break;
}

Another solution I can think of is to use Array of Arrays instead of the object:

var obj = [['key1', 'value1'], ['key2', 'value2']];

Then, standard for loop will work.