Feature Request: add prefix to mangled variable about uglifyjs

[alexlamsl]

Consider using name cache (--name-cache on CLI or nameCache on API), which tracks renaming of variables thus avoid clashes which you experience.

[DEVTomatoCake]

How is nameCache supposed to work, @alexlamsl?

I thought it stores all variables it minified, thus preventing the re-use of mangled names.
However, it looks like it only stores them in the supplied object when minifying a top level variable; if toplevel is set to false, the object is left unchanged.

I've encountered this because a constant at the top level named url was minified to n (which was reflected in the object), but in another file, lang was also renamed to n in an anonymous function.
This obviously causes errors, especially as the const which was in front of lang was also removed, causing it to use the global scope.

Original:

// script.js
const url = "https://api.tomatenkuchen.com/api/"

// language.js
const getLanguage = () => {
	if (getCookie("lang")) return getCookie("lang")

	const userLang = navigator.language || navigator.userLanguage
	if (userLang) {
		const lang = userLang.split("-")[0]
		return lang == "de" || lang == "fr" || lang == "hu" || lang == "ja" ? lang : "en"
	}
	return "en"
}

Minified/mangled:

// script.js
const n="https://api.tomatenkuchen.com/api/"; // [...]

// language.js
const getLanguage=()=>getCookie("lang")?getCookie("lang"):!(n=navigator.language||navigator.userLanguage)||"de"!=(n=n.split("-")[0])&&"fr"!=n&&"hu"!=n&&"ja"!=n?"en":n // [...]

It's quite difficult to provide something easily reproducible, it's probably just caused by having many mangled variables.
I can try to create something easier to reproduce if needed.