Getting an Invalid left-hand side in assignment

Question

I'm getting an Uncaught SyntaxError: Invalid left-hand side in assignment error for

[d1,d2] =[d2,d1];

Anyone know why?

Here's a (present day) javascript compliant variable swap: http://stackoverflow.com/questions/16201656/how-to-swap-two-variables-in-javascript — bloodyKnuckles, Jun 16 '14 at 14:21
Current JavaScript doesn't work like that. But it looks like ECMAScript 6 might. — Andy, Jun 16 '14 at 14:22
This isn't supported by all (or afaik many at all) browsers. http://stackoverflow.com/questions/6983026/javascript-assign-array-values-to-multiple-variables — James, Jun 16 '14 at 14:22
@PatrickHofman It is some code in a library I am using. It's in a function I probably won't use anyway since I don't foresee any need for it in the project I'm coding up. Thanks for the compliant code. Thank you all. — Sultan Shakir, Jun 16 '14 at 15:00

score 1 · Accepted Answer · edited May 23 '17 at 12:07

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You have probably done a good try by looking at other posts here at SO, since your code looks much like the one at this comment.

Unfortunately, the feature you use runs with ECMAScript 6, and that isn't supported on all browsers (yet) as you can see here and more specific this one.

You should use the code in the answer this comment was under.

d2 = [d1, d1 = d2][0];

edited May 23 '17 at 12:07

Community

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answered Jun 16 '14 at 14:25

Patrick Hofman

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"ECMAScript isn't supported on all browsers" doesn't really make sense, because in present-day parlance JavaScript is an implementation of ECMAScript. Every common browser today supports at least ECMAScript 3 ([as JavaScript 1.5](http://en.wikipedia.org/wiki/JavaScript#Version_history)) and, as the chart you linked to shows, most of ECMAScript 5. (ES4 was "skipped" for political reasons.) It would be more accurate to say that destructuring assignment is an ECMAScript 6 draft specification feature and [isn't supported in all browsers](http://kangax.github.io/compat-table/es6/#Destructuring). – Jordan Running Jun 16 '14 at 14:39

score 1 · Answer 2 · answered Jun 16 '14 at 14:36

To run this code you must wait for ECMA6 implementation - http://www.2ality.com/2014/06/es6-multiple-return-values.html

Getting an Invalid left-hand side in assignment

2 Answers2