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feat(minifier): remove typeof guarded global access expressions #13751

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Merged
merged 1 commit into from
Sep 14, 2025
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feat(minifier): remove typeof guarded global access expressions #13751

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16 changes: 16 additions & 0 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 @@ -65,6 +65,9 @@ impl<'a> PeepholeOptimizations {
}

fn remove_unused_logical_expr(e: &mut Expression<'a>, ctx: &mut Ctx<'a, '_>) -> bool {
if !e.may_have_side_effects(ctx) {
return true;
}
let Expression::LogicalExpression(logical_expr) = e else { return false };
if !logical_expr.operator.is_coalesce() {
Self::minimize_expression_in_boolean_context(&mut logical_expr.left, ctx);
Expand Down Expand Up @@ -378,6 +381,9 @@ impl<'a> PeepholeOptimizations {
}

fn remove_unused_conditional_expr(e: &mut Expression<'a>, ctx: &mut Ctx<'a, '_>) -> bool {
if !e.may_have_side_effects(ctx) {
return true;
}
let Expression::ConditionalExpression(conditional_expr) = e else {
return false;
};
Expand Down Expand Up @@ -884,6 +890,11 @@ mod test {
test_same("v = a == null && (a = b)");
test_same("v = a != null || (a = b)");
test("void (x == null && y)", "x ?? y");

test("typeof x != 'undefined' && x", "");
test("typeof x == 'undefined' || x", "");
test("typeof x < 'u' && x", "");
test("typeof x > 'u' || x", "");
}

#[expect(clippy::literal_string_with_formatting_args)]
Expand Down Expand Up @@ -925,6 +936,11 @@ mod test {
test("foo() ? 1 : bar()", "foo() || bar()");
test("foo() ? bar() : 2", "foo() && bar()");
test_same("foo() ? bar() : baz()");

test("typeof x == 'undefined' ? 0 : x", "");
test("typeof x != 'undefined' ? x : 0", "");
test("typeof x > 'u' ? 0 : x", "");
test("typeof x < 'u' ? x : 0", "");
}

#[test]
Expand Down
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