FR: Further opportunities to DCE unused object methods

[samouri]

summary

Today I ran into a few surprising behaviors that I believe could be optimized.
I've figured out workarounds for them, but figured it would be good to post them here in case folks were interested in fixing them.

happy case: regular object properties

qux is unused and DCE'd.

const Foo = {
  bar: () => console.log('bar'),
  qux: () => console.log('qux'),
}

Foo.bar();

object methods

qux is unused yet retained.

const Foo = {
  bar() { console.log('bar')}
  qux() { console.log('qux')}
}

Foo.bar();

self-referencing object

qux is unused yet retained.

const Foo = {
  bar: () => console.log('bar'),
  qux: () => Foo.bar(),
}

Foo.bar();

function literal vs. reference

optimally optimized

function bar() { console.log('bar') }
const Foo = { bar: () => bar() }
Foo.bar();

deopted

function bar() { console.log('bar') }
const Foo = { bar }
Foo.bar();

[jridgewell]

I'm going to split this into two bugs: One for supporting DCE of object methods, and one for supporting self-referencing objects in DCE.