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feat(minifier): dce all conditional expressions (#4135)

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Boshen 2024-07-09 18:28:33 +08:00 committed by GitHub
parent cb1af043b8
commit c6c16a5fc9
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2 changed files with 11 additions and 9 deletions
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17
crates/oxc_minifier/src/ast_passes/remove_dead_code.rs
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@ -44,20 +44,16 @@ impl<'a> RemoveDeadCode<'a> {
} }
} }
pub fn remove_conditional(&mut self, stmt: &mut Statement<'a>) { pub fn remove_conditional(&mut self, expr: &mut Expression<'a>) {
let Statement::ExpressionStatement(expression_stmt) = stmt else { return }; let Expression::ConditionalExpression(conditional_expr) = expr else {
let Expression::ConditionalExpression(conditional_expr) = &mut expression_stmt.expression
else {
return; return;
}; };
match self.test_expression(&mut conditional_expr.test) { match self.test_expression(&mut conditional_expr.test) {
Some(true) => { Some(true) => {
expression_stmt.expression = *expr = self.ast.move_expression(&mut conditional_expr.consequent);
self.ast.move_expression(&mut conditional_expr.consequent);
} }
Some(false) => { Some(false) => {
expression_stmt.expression = *expr = self.ast.move_expression(&mut conditional_expr.alternate);
self.ast.move_expression(&mut conditional_expr.alternate);
} }
_ => {} _ => {}
} }
@ -67,7 +63,10 @@ impl<'a> RemoveDeadCode<'a> {
impl<'a> VisitMut<'a> for RemoveDeadCode<'a> { impl<'a> VisitMut<'a> for RemoveDeadCode<'a> {
fn visit_statement(&mut self, stmt: &mut Statement<'a>) { fn visit_statement(&mut self, stmt: &mut Statement<'a>) {
self.remove_if(stmt); self.remove_if(stmt);
self.remove_conditional(stmt);
walk_mut::walk_statement(self, stmt); walk_mut::walk_statement(self, stmt);
} }
fn visit_expression(&mut self, expr: &mut Expression<'a>) {
self.remove_conditional(expr);
}
} }

3
crates/oxc_minifier/tests/oxc/remove_dead_code.rs
View file

@ -42,6 +42,9 @@ fn remove_dead_code() {
test("!!false ? foo : bar;", "bar"); test("!!false ? foo : bar;", "bar");
test("!!true ? foo : bar;", "foo"); test("!!true ? foo : bar;", "foo");
test("const foo = true ? A : B", "const foo=A");
test("const foo = false ? A : B", "const foo=B");
// Shadowed `undefined` as a variable should not be erased. // Shadowed `undefined` as a variable should not be erased.
test( test(
"function foo(undefined) { if (!undefined) { } }", "function foo(undefined) { if (!undefined) { } }",