Possible to assign to multiple variables from an array?

Question

Is it a standard way to assign to multiple variables from an array in JavaScript? In Firefox and Opera, you can do:

var [key, value] = "key:value".split(":");
alert(key + "=" + value); // will alert "key = value";

But it doesn't work in IE8 or Google Chrome.

Does anyone know a nice way to do this in other browsers without a tmp variable?

var tmp = "key:value".split(":");
var key=tmp[0], value=tmp[1];

Is this something that will come in an upcoming JavaScript version, or just custom implementation in FF and Opera?

Answer 1

I think it should be a part of the new spec., then again it's a long read... :p

key = "key:value".split(":")[0];
value = "key:value".split(":")[1];

Only alternative I can think off.

Answer 2

I don't think this is possible in a cross browser way. The best that I know which might help in a few circumstances is this:

// we'll pretend you don't need the key.
var value = "key:value".split(":")[1];

Answer 3

I don't know how you are using this, but if I was able to determine my own format for the "key:value" string, I'd be tempted to use json to just eval the string into the necessary object:

var obj = eval("{'key':'key_str', 'value':'val_str'}");
alert(obj.key + "=" + ojb.value);  //alerts "key_str=value_str

Answer 4

If you want to know what's coming, read the section on Destructuring Assignment.

https://developer.mozilla.org/en/New_in_javascript_1.7

What language features you can use is always dependent on your environment.

Developing for Mobile Safari (or a web stack for other browsers like the Palm Pre, Android, etc.) or AIR, for example, is more predictable than developing for the web at large (where you still have to take even IE6 into account).

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A cross-browser solution to the problem at hand would be to initialize an array that had a list of the variables you want to fill in window.variable format, then just loop through. Can't imagine why you'd do it though. Seems like there would always be a better solution.