@lukastaegert I noticed Object.entries was added recently as pure function. I was always wondering what constitutes a pure function?

I thought a pure function is one without side effects, e.g.

Object.keys:
https://rollupjs.org/repl/?version=2.70.2&shareable=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

compare to: Object.values:
https://rollupjs.org/repl/?version=2.70.2&shareable=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

which should behave the same as Object.entries:
https://rollupjs.org/repl/?version=2.70.2&shareable=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@lukastaegert I noticed Object.entries was added recently as pure function. I was always wondering what constitutes a pure function?

You are right, with the current simple logic all of them should not be marked as pure. To solve this in a good way, we would need a way to specify a function iterates the keys of its argument and is pure if there are no own property getters.

The global logic is very dumb at the moment as it only understands a single flag—pure.

Compare this with the much more advanced logic for builtin prototypes (which ideally should be merged with the globals logic at some point):

Here we know a return value and can specify that an argument is called (but do not know about iterating keys because that was not needed).

So we could add a flag that says something like accessesArgumentProps and calling it has a side effect if

callOptions.args[0].hasEffectsWhenAccessedAtPath(UNKNOWN_PATH, context)