1289459 - JavaScript const in (for ...of) throws Syntax Error

Status: RESOLVED DUPLICATE of bug 1101653

(Core :: JavaScript Engine, defect)

Description

[swood]

Using the for...of loop construct with the const keyword throws a Syntax Error. The MDN documentation suggests this construct on the second example on this page: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of

The error thrown is "SyntaxError: missing = in const declaration".  The for...of loop works with the var and let keyword when used in the same way.

Code:
for (const n of [1, 2, 3]) { console.log(n); }

Comment 1

[Jeff Walden [:Waldo]]

Known bug.  A wide-ranging rewrite of our parser (bug 1263355), mostly complete now except for dealing with some perf concerns and the full gamut of tbpl tests, should fix this in the next few months on trunk.