Description of problem:

I am trying to update js-jsroot to version 6, which is a major update where the developers have started using syntax from newer versions of javascript.

This new syntax is not understood by the uglifyjs version in Fedora.
For example:

<mock-chroot> sh-5.1# uglifyjs --version
uglify-js 3.10.4

<mock-chroot> sh-5.1# uglifyjs JSRoot.core.js -c -m -o JSRoot.core.min-1.js 
Parse error at JSRoot.core.js:7,10
      let jsroot = factory({}),
          ^
ERROR: Unexpected token: name «jsroot», expected: punc «;»
    at JS_Parse_Error.get (eval at <anonymous> (/usr/lib/node_modules/uglify-js@3/tools/node.js:18:1), <anonymous>:71:23)
    at fatal (/usr/lib/node_modules/uglify-js@3/bin/uglifyjs:394:27)
    at run (/usr/lib/node_modules/uglify-js@3/bin/uglifyjs:343:9)
    at Object.<anonymous> (/usr/lib/node_modules/uglify-js@3/bin/uglifyjs:259:5)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
    at internal/main/run_main_module.js:17:47

<mock-chroot> sh-5.1# uglifyjs JSRoot.latex.js -c -m -o JSRoot.latex.min-1.js 
Parse error at JSRoot.latex.js:4,44
JSROOT.define(['d3', 'painter'], (d3, jsrp) => {
                                            ^
ERROR: Invalid assignment
    at JS_Parse_Error.get (eval at <anonymous> (/usr/lib/node_modules/uglify-js@3/tools/node.js:18:1), <anonymous>:71:23)
    at fatal (/usr/lib/node_modules/uglify-js@3/bin/uglifyjs:394:27)
    at run (/usr/lib/node_modules/uglify-js@3/bin/uglifyjs:343:9)
    at Object.<anonymous> (/usr/lib/node_modules/uglify-js@3/bin/uglifyjs:259:5)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
    at internal/main/run_main_module.js:17:47

If I build an updated package from the latest version of uglify-js, and use that it works:

<mock-chroot> sh-5.1# uglifyjs --version
uglify-js 3.13.4
<mock-chroot> sh-5.1# uglifyjs JSRoot.core.js -c -m -o JSRoot.core.min-2.js 
<mock-chroot> sh-5.1# uglifyjs JSRoot.latex.js -c -m -o JSRoot.latex.min-2.js 

But for packaging of packages in koji, I can't use my own private updated package, but need the update in Fedora proper.


Version-Release number of selected component (if applicable):

uglify-js-3.10.4-1.fc34
uglify-js-3.10.4-2.fc34

How reproducible:

Always.

Steps to Reproduce:
1. Try minifying a script using mor modern javascript syntax (see example above)

Actual results:

Minifying fails.

Expected results:

Minifying works.

Additional info:

As a minimum I would like this updated in Fedora releases using uglify-js version 3 (i.e. Fedora 34 and above).
Preferably for all current releases (i.e. 33 and maybe 32 - though 32 is soon EOL so it is not super important).
In EPEL 8 uglify-js is provided by RHEL/CentOS and not by EPEL, so there a parallel installable uglify-js3 package will be needed.
As the maintainer of the main uglify-js package, do you wish to maintain such a package or do you prefer someone else to do it?
In EPEL 7 uglify-js is provided by EPEL, so in priciple it can be updated. But having a newer version in EPEL 7 than in RHEL 8 might be odd - so possibly adding the uglify-js3 package there too might make more sense. What do you think?
If you prefer to keep Fedora 33 on version 2, the uglify-js3 package can be added there too.