How well is the `for of` JavaScript statement supported? [closed]

Question

var nameArray = [

{ name: 'john', surname: 'smith'  },
{ name: 'paul', surname: 'jones' },
{ name: 'timi', surname: 'abel' },

];  

for (str of nameArray) {    
   console.log( str.name );

}

I want to know, how supported is for( item of array ) in terms of browser support, mobile JavaScript support - I realize you cannot do greater than > and this is pure iteration?

I have just discovered this, is this as good as I hope it is?

Answer 1

The classic way of doing this is as follows:

  for(var i = 0; i < nameArray.length; i++){
    var str = nameArray[i];
  }

This will give you the exact functionality of a "foreach" loop, which I suspect is what you're really after here. This also gives you the added benefit of working in Internet Explorer.

There is also extensive knowledge of the exact loop described in the MDN. At this time Android web and it seems not everything supports your method so check the compatibility list on that page; seems to be a future release of the new JavaScript that will probably have OOP inside it.

Answer 2

MDN:

While for...in iterates over property names, for...of iterates over property values.

The above is what for...of loop does. The below is its current status.

This is an experimental technology, part of the Harmony (ECMAScript 6) proposal. Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future version of browsers as the spec changes.

Answer 3

This is the ES6 for..of loop. According to the MDN article i just linked, it's supported by several browsers (see there for exact versions), but not IE. Currently, several mobile browsers also support it.

Answer 4

In the meantime, you could use something like this:

for(element_idx in elements) {
    element = elements[element_idx];
    ...
}

for...in has been standard since ECMAScript 1st Edition.

Answer 5

It's not.

Even if it were, it would be inappropriate to use it on an array.

For arrays, you should always use a traditional for loop.

You can, however, spice it up a bit:

for( var i=0, l=nameArray.length, str=nameArray[0];
     i<l;
     i++,str=nameArray[i]) {
  console.log(str.name);
}