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perf(codegen): optimize Codegen::print_list method #10242

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graphite-app merged 1 commit into from
Apr 7, 2025
Merged

perf(codegen): optimize Codegen::print_list method #10242

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26 changes: 8 additions & 18 deletions crates/oxc_codegen/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -455,25 +455,15 @@ impl<'a> Codegen<'a> {
self.needs_semicolon = false;
}

// We tried optimizing this to move the `index != 0` check out of the loop:
// ```
// let mut iter = items.iter();
// let Some(item) = iter.next() else { return };
// item.print(self, ctx);
// for item in iter {
// self.print_comma();
// self.print_soft_space();
// item.print(self, ctx);
// }
// ```
// But it turned out this was actually a bit slower.
// <https://github.com/oxc-project/oxc/pull/5221>
#[inline]
fn print_list<T: Gen>(&mut self, items: &[T], ctx: Context) {
for (index, item) in items.iter().enumerate() {
if index != 0 {
self.print_comma();
self.print_soft_space();
}
let Some((first, rest)) = items.split_first() else {
return;
};
first.print(self, ctx);
for item in rest {
self.print_comma();
self.print_soft_space();
item.print(self, ctx);
}
}
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