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fix(minifier): keep classes with static properties + side effect initializer #12848

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Merged
merged 1 commit into from
Aug 6, 2025
Merged

fix(minifier): keep classes with static properties + side effect initializer #12848

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12 changes: 5 additions & 7 deletions crates/oxc_minifier/src/peephole/remove_unused_declaration.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -130,23 +130,21 @@ mod test {
test_options("class C { foo }", "", &options);
test_options("class C { foo = bar }", "", &options);
test_options("class C { foo = 1 }", "", &options);
test_options("class C { static foo = bar }", "bar", &options);
// TODO: would be nice if this is removed but the one with `this` is kept.
test_same_options("class C { static foo = bar }", &options);
test_same_options("class C { static foo = this.bar = {} }", &options);
test_options("class C { static foo = 1 }", "", &options);
test_options("class C { [foo] = bar }", "foo", &options);
test_options("class C { [foo] = 1 }", "foo", &options);
test_options("class C { static [foo] = bar }", "foo, bar", &options);
test_same_options("class C { static [foo] = bar }", &options);
test_options("class C { static [foo] = 1 }", "foo", &options);

// accessor
test_options("class C { accessor foo = 1 }", "", &options);
test_options("class C { accessor [foo] = 1 }", "foo", &options);

// order
test_options(
"class _ extends A { static [B] = C; static [D]() {} }",
"A, B, C, D",
&options,
);
test_options("class _ extends A { [B] = C; [D]() {} }", "A, B, D", &options);

// decorators
test_same_options("class C { @dec foo() {} }", &options);
Expand Down
36 changes: 21 additions & 15 deletions crates/oxc_minifier/src/peephole/remove_unused_expression.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -674,20 +674,29 @@ impl<'a> PeepholeOptimizations {
{
return None;
}
// Keep the entire class if non-empty static block exists.
// Keep the entire class if there are class level side effects.
for e in &c.body.body {
match e {
e if e.has_decorator() => return None,
ClassElement::TSIndexSignature(_) => return None,
ClassElement::StaticBlock(block) => {
if !block.body.is_empty() {
return None;
}
ClassElement::StaticBlock(block) if !block.body.is_empty() => return None,
ClassElement::PropertyDefinition(prop)
if prop.r#static
&& prop.value.as_ref().is_some_and(|v| v.may_have_side_effects(ctx)) =>
{
return None;
}
ClassElement::AccessorProperty(prop)
if prop.r#static
&& prop.value.as_ref().is_some_and(|v| v.may_have_side_effects(ctx)) =>
{
return None;
}
_ => {}
}
}

// Otherwise extract the expressions.
let mut exprs = ctx.ast.vec();

if let Some(e) = &mut c.super_class {
Expand Down Expand Up @@ -721,9 +730,8 @@ impl<'a> PeepholeOptimizations {
ClassElement::PropertyDefinition(def) => def.value.take(),
ClassElement::AccessorProperty(def) => def.value.take(),
} {
if init.may_have_side_effects(ctx) {
exprs.push(init);
}
// Already checked side effects above.
exprs.push(init);
}
}
}
Expand Down Expand Up @@ -1115,23 +1123,21 @@ mod test {
test_options("(class { foo })", "", &options);
test_options("(class { foo = bar })", "", &options);
test_options("(class { foo = 1 })", "", &options);
test_options("(class { static foo = bar })", "bar", &options);
// TODO: would be nice if this is removed but the one with `this` is kept.
test_same_options("(class { static foo = bar })", &options);
test_same_options("(class { static foo = this.bar = {} })", &options);
test_options("(class { static foo = 1 })", "", &options);
test_options("(class { [foo] = bar })", "foo", &options);
test_options("(class { [foo] = 1 })", "foo", &options);
test_options("(class { static [foo] = bar })", "foo, bar", &options);
test_same_options("(class { static [foo] = bar })", &options);
test_options("(class { static [foo] = 1 })", "foo", &options);

// accessor
test_options("(class { accessor foo = 1 })", "", &options);
test_options("(class { accessor [foo] = 1 })", "foo", &options);

// order
test_options(
"(class extends A { static [B] = C; static [D]() {} })",
"A, B, C, D",
&options,
);
test_options("(class extends A { [B] = C; [D]() {} })", "A, B, D", &options);

// decorators
test_same_options("(class { @dec foo() {} })", &options);
Expand Down
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