Is there any other way in "use strict"; javascript to initialize a value to multiple variables? Because doing this:
var x = y = 14;
will cause error: Uncaught ReferenceError: y is not defined
Got my reference here:
2 Answers
There are side affects to var x = y = 14; which is why it's not allowed in strict mode. Namely, y becomes a global variable.
When you say
var x = y = 14;
It is equivalent to
var x;
y = 14;
x = y;
Where x is declared as a local variable and y is created as a global variable.
For more information on using var to declare variables see this question. Additionally, it may be worth noting that ES6 is introducing the keyword let that enables block level scoping in contrast to function level scoping that exists with var.
Finally, if you want to assign both variables a value, any of the following would do
var x, y;
x = y = 14;
var x = 14,
y = x;
var x = 14,
y = 14;
var x = 14;
var y = 14;
9 Comments
Niet the Dark Absol
The last example still makes
y global, does it not?
Felix Kling
Actually,
var x = y = 14; is equivalent to y = 14; var x = 14;. But I guess the order is not very important. In that case.
sfletche
You are correct. Thanks @FelixKling. Edited my answer to reflect your correction.
Felix Kling
I was wrong. You were correct that it is
var x = 14; (because y = 14) results in 14.Niet the Dark Absol
@FelixKling If you want to get specific, it's equivalent to
var x; y = 14; x = y; :D |
Yup - don't mix declarations and assignments.
var x, y;
x = y = 14;
answered May 5, 2015 at 3:10
Niet the Dark Absol
326k86 gold badges480 silver badges604 bronze badges
x