Uglifier runs into problems with certain combination of modern JS syntax (await, destructuring, Promise.all)

[chris-geelhoed]

Hi there,

Version (4.2.0)

My JS compressor settings are this:

  config.assets.js_compressor = Uglifier.new({
    harmony: true, # Required for ES6 scripts
    output: {
      comments: :none, # Remove absolutely every comment
      max_line_len: 512, # Automatically wrap minified lines to 512 characters
    }
  })

On rake assets:precompile I get this error:

excluded from capture: DSN not set
rake aborted!
Uglifier::Error:

After a lot of trial and error and debugging I was able to deduce the issue to be this syntax:

var [defaultsRes, selectedData] = await Promise.all(reqs);

The code ran as expected in development but could not be handled by the prod uglifier settings (noted above). Switching to the following fixed things for me:

var responses = await Promise.all(reqs);
var defaultsRes = responses[0];
var selectedData = responses[1];

Thanks!

[selfawaresoup]

Anything happening on this issue? I just ran into the same problem. No error message or line number so I had to remove pieces of my JS code to narrow down where Uglifier failed. Turned out to be a destructuring statement.