JavaScript alternative to "for each" loop

Question

According to the MDN page at for each...in loop, this construct is deprecated. Is there an alternative that does exactly the same thing? The for...of loop does not iterate over non-integer (own enumerable) properties. If there isn't an alternative, why did they deprecate it then?

Solution 1

Is there an alternative that does exactly the same thing?

A for ... in loop in which the first thing you do in the block of code is to copy foo[propertyname] to a variable.

Solution 2

To iterate over all the properties of an object obj, you may do this :

for (var key in obj) {
   console.log(key, obj[key]);
}

If you want to avoid inherited properties, you may do this :

for (var key in obj) {
   if (!obj.hasOwnProperty(key)) continue;
   console.log(key, obj[key]);
}

Solution 3

You can make use of the new ECMAScript 5th Edition functions:

Object.keys(obj).forEach(function (key) {
    console.log(key, obj[key]);
});

Comments

[noel]

Good point made here

[user1537366]

Yes, I guess there is only this work-around, which isn't really a language replacement for "for each". So they shouldn't have deprecated it, right?

[Quentin]

@Benedictus — No. It's in JavaScript 1.0. Netscape 2 supports it!

[pherris]

^ this is how I solved the no-restricted-syntax error from eslint when the forinstatement is used.