Question

On a Play Framework 2 project if I have any javascript code with this simple statements like that:

const num = 3;

I get the error:
Parse error. Unsupported syntax: CONST

I see that Play Framework has a Javascript Compiler and, from I what I get, minifies your javascript automatically but are consts really not supported ?? It is fundamental language syntax…

Answer 1

Note that while “const” is reserved as a future keyword by the ECMAScript specification, Mozilla and most other browsers implement it as a non-standard extension that may be standardized in a future version of ECMAScript.

source

If you really want it to be non-editable (I DO NOT RECOMMEND DOING THIS), you could use getters and setters:

window.__defineGetter__('num', function () {
    return 3;
});

window.__defineSetter__('num', function () {
    // nada, it's a constant
});

http://jsfiddle.net/tp2HU/