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fix(minifier): do not remove undefined in var x = undefined (#8526)

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Boshen 2025-01-16 02:57:28 +00:00
parent 06f14d526b
commit 92e44cba6b
1 changed files with 7 additions and 5 deletions
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12
crates/oxc_minifier/src/ast_passes/peephole_substitute_alternate_syntax.rs
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@ -665,7 +665,9 @@ impl<'a, 'b> PeepholeSubstituteAlternateSyntax {
if decl.kind.is_const() || decl.id.kind.is_destructuring_pattern() { if decl.kind.is_const() || decl.id.kind.is_destructuring_pattern() {
return; return;
} }
if decl.init.as_ref().is_some_and(|init| ctx.is_expression_undefined(init)) { if !decl.kind.is_var()
&& decl.init.as_ref().is_some_and(|init| ctx.is_expression_undefined(init))
{
decl.init = None; decl.init = None;
self.changed = true; self.changed = true;
} }
@ -1281,17 +1283,17 @@ mod test {
#[test] #[test]
fn test_undefined() { fn test_undefined() {
test("var x = undefined", "var x"); test("let x = undefined", "let x");
test("const x = undefined", "const x = void 0");
test("var x = undefined", "var x = void 0");
test_same("var undefined = 1;function f() {var undefined=2;var x;}"); test_same("var undefined = 1;function f() {var undefined=2;var x;}");
test_same("function f(undefined) {}"); test_same("function f(undefined) {}");
test_same("try {} catch(undefined) {foo(undefined)}"); test_same("try {} catch(undefined) {foo(undefined)}");
test("for (undefined in {}) {}", "for(undefined in {}){}"); test("for (undefined in {}) {}", "for(undefined in {}){}");
test("undefined++;", "undefined++"); test("undefined++;", "undefined++");
test("undefined += undefined;", "undefined+=void 0"); test("undefined += undefined;", "undefined+=void 0");
// shadowed
// shadowd
test_same("(function(undefined) { let x = typeof undefined; })()"); test_same("(function(undefined) { let x = typeof undefined; })()");
// destructuring throw error side effect // destructuring throw error side effect
test_same("var {} = void 0"); test_same("var {} = void 0");
test_same("var [] = void 0"); test_same("var [] = void 0");