Erroneous minification when using arrow function parameter list

[Darkov3]

Installed product versions

• Visual Studio: 2019 Enterprise
• This extension: 2.8.396 VS Extension

Description

When a js file contains an arrow function parameter list, the minified result is malformed.

Steps to recreate

1. Create a JS file with this content:

var test = [[1, 2], [2, 3], [3, 4]];
var testFilter = [];
test.filter(([index1, index2]) => testFilter.push(index1 + index2));
console.log(testFilter);

2. Minify it.
3. Run the minified result and you will get a malformed error.

Current behavior

It will currently minify the above code to:

var test=[[1,2],[2,3],[3,4]],testFilter=[];test.filter([n,t]=>testFilter.push(n+t));console.log(testFilter);

Which is missing brakets around [n,t].

Expected behavior

The result should be runnable JS, or in this case, its missing brackets, the corrected version is:

var test=[[1,2],[2,3],[3,4]],testFilter=[];test.filter(([n,t])=>testFilter.push(n+t));console.log(testFilter);

[Dean-NC]

Yes, it's a bug.

Paste the code here and see a good result: https://skalman.github.io/UglifyJS-online

[sanmolhec]

I have the same problem.

Do not minify with the arrow syntax or features of ES8.

I find the nuget package very useful but I would have to minify the more modern JS.

Thanks!!