Flask Bundle remove white space after variables enclosed in ${} in Template strings in JavaScript

[Rongeegee]

So in my production environment, i use Bundle imported from flask_assets.

from flask_assets import Environment, Bundle

JS_BUNDLE = Bundle('js/modules/xxxxx.js',......,'js/modules/xxxxx.js',
                   filters=filters, output='js/bundle/scripts.custom.%s.min.js' % RELEASE_VERSION)

assets = Environment(app)
assets.register('js_custom', JS_BUNDLE)

Then in my JavaScript file, I have the following

const date = new Date();

const day = date.getDate() >= 10 ? date.getDate() :  "0" + date.getDate() ;
const month = date.toLocaleString('default', { month: 'long' }).substring(0,3);
const year = date.getFullYear();

const englishDate = `${day} ${month}, ${year}`;

Suppose that today's date is 6/8/2023. The englishDate is supposed to have a string value of "08 Jun, 2023". However, the value it got on production after the bundle is "08Jun,2023". All the spaces within the string is removed.

I checked the bundled file, it turned out that the spaces are remove in the code when being bundled. The last line became

const englishDate = `${day}${month},${year}`;

However, If I don't use variables inside the string enclosed by backticks (`). Such as

const englishDate = `June 8th,  2023`;

All the spaces in the string will be preserved.

It seems like this issue only happened when a variable is used within a template string. All the spaces followed by the variable will be removed by the bundler.

Can anyone replicate it and let me know?