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fix(minifier): omit dce undefined which can be a shadowed variable #4073

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Merged
Boshen merged 1 commit into from
Jul 6, 2024
Merged

fix(minifier): omit dce undefined which can be a shadowed variable #4073

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3 changes: 2 additions & 1 deletion crates/oxc_minifier/src/compressor/ast_util.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -485,7 +485,8 @@ pub fn get_boolean_value(expr: &Expression) -> Option<bool> {
.map(|cooked| !cooked.is_empty())
}
Expression::Identifier(ident) => {
if expr.is_undefined() || ident.name == "NaN" {
/* `undefined` can be a shadowed variable expr.is_undefined() || */
if ident.name == "NaN" {
Some(false)
} else if ident.name == "Infinity" {
Some(true)
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6 changes: 6 additions & 0 deletions crates/oxc_minifier/tests/oxc/remove_dead_code.rs
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Expand Up @@ -41,4 +41,10 @@ fn remove_dead_code() {

test("!!false ? foo : bar;", "bar");
test("!!true ? foo : bar;", "foo");

// Shadowed `undefined` as a variable should not be erased.
test(
"function foo(undefined) { if (!undefined) { } }",
"function foo(undefined){if(!undefined){}}",
);
}