Pipeline Champions
2022-02-16
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16:23
<jschoi>
nicolo-ribaudo published https://github.com/babel/babel/pull/14278. It tries to inline topic references by replacing them with their LHSes when they’re pure. Very cool!
16:24
<jschoi>
I hadn’t known that a path.isPure method was already implemented in Babel…
16:26
<nicolo-ribaudo>
We already use it to optimize in multiple places!
16:28
<nicolo-ribaudo>

The next step will be to introduce an "assume that imported bindings are constant" option, since it's what will help in most cases. Otherwise this code still needs tmp vars:

import { map, filter } from "array";
val
  |> map(#, x => x + 2)
  |> filter(#, x => x > 3)
16:29
<nicolo-ribaudo>
because a call to map might change what filter is
16:30
<pokute>
I'm interested in which of these assumptions would apply for TypeScript downlevel transformations too.
16:35
<pokute>
I wonder if TS has such purity checks too. I guess optimizing even literals would be helpful...
22:34
<TabAtkins>
Ah the purity constraint is because of the swapped order of evaluation, interesting