'Syntax error, unexpected token =' in js function

Question

I am getting this error in chrome while mozilla is handling good. I am getting this error to a function which is like this

function abc( xyz = false){ "My logic" }

Error is pointing to '=' operator. please help with this.

No default argument as of ES5, `function abc( xyz){ xyz = xyz || false; "My logic" }` — Tushar, Oct 26 '15 at 07:27
What's going on with `xyz = false`? The compiler is expecting an identifier there, but is getting an assignment. — Hunan Rostomyan, Oct 26 '15 at 07:27
Mozilla supports default parameters while Chrome is not yet. — dfsq, Oct 26 '15 at 07:28
You can check here for es6 [compatibility table](https://kangax.github.io/compat-table/es6/). See "default function parameters": — Ziki, Oct 26 '15 at 07:30
jesus... how people are misusing their power of reputation...!!! — Rahul Gupta, Oct 26 '15 at 08:02

Jai · Accepted Answer · 2015-10-26T07:41:59.013

4

That is a standard of ECMASCRIPT version 6 and it's called Default parameters. So it might be not available in your chrome version while FF has.

You can achieve the same by two ways:

function abc( xyz ){ "My logic" }

var pVal = mightbe || false;
abc(pVal); //<---- now pass it here;

or:

function abc( xyz ){ 
    // before processing anything you can do this
    var o = xyz || false; // if there is any value in the xyz then that will
                          // be assigned otherwise false will be the default value.
    "My logic" 
}

edited Oct 26 '15 at 07:41

answered Oct 26 '15 at 07:29

Jai

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It has nothing to do with destructuring, it's different thing. – dfsq Oct 26 '15 at 07:32
Although you're right about being an ES6 standard, the name is Default Parameters. Destructuring assignment is only a subset of it, e.g: `function f([x, y] = [1, 2], {z: z} = {z: 3}) {`. – Buzinas Oct 26 '15 at 07:32

score 0 · Answer 2 · answered Oct 26 '15 at 07:32

This is ES6 syntax, most browsers only support very few ES6 features, you can check from here: https://kangax.github.io/compat-table/es6/ (In your example you used default function parameters)

If you want to write ES6 syntax (which is quite appealing in many ways), you can use some code transpiling tool like babel: https://babeljs.io/

'Syntax error, unexpected token =' in js function

2 Answers2