the unused var not be removed

[HomyeeKing]

Rollup Version

latest

Operating System (or Browser)

OSX Chrome

Node Version (if applicable)

No response

Link To Reproduction

https://rollupjs.org/repl/?version=3.2.3&shareable=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

Expected Behaviour

only isTrue remained

Actual Behaviour

the unused constant ua and others are included

[lukastaegert]

You have to put your pure annotations into places where they have an effect. They are only observed for call expressions (that is also how it works in Unglify/Terser) https://rollupjs.org/repl/?version=3.2.3&shareable=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

[HomyeeKing]

@lukastaegert what's the effect of the regular expression?

[lukastaegert]

Nobody programmed it into Rollup.

[HomyeeKing]

@lukastaegert also why remain import 'lodash-es'

reproduce link

[lukastaegert]

Because every external import can have side effects that we do not know about. If you are sure there are none, look into the treeshake.moduleSideEffects option.

[HomyeeKing]

Thanks a lot! I've been confused these days because I thought the treeshaking strategy remove those unused package by default

[lukastaegert]

There is one actionable point left in this issue, which is to declare suitable regular expression prototype methods as side effect free, similar how we do e.g. for string prototype methods.

[rollup-bot]

This issue has been resolved via #4737 as part of rollup@3.7.0. You can test it via npm install rollup.