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feat(minifier): minimize empty try statement (#8309)

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Boshen 2025-01-07 07:16:01 +00:00
parent e1f8ea41ad
commit 4b68cc0972
1 changed files with 44 additions and 7 deletions
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51
crates/oxc_minifier/src/ast_passes/peephole_remove_dead_code.rs
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@ -30,13 +30,12 @@ impl<'a> Traverse<'a> for PeepholeRemoveDeadCode {
fn exit_statement(&mut self, stmt: &mut Statement<'a>, ctx: &mut TraverseCtx<'a>) {
let ctx = Ctx(ctx);
if let Some(new_stmt) = match stmt {
Statement::BlockStatement(block_stmt) => Self::try_optimize_block(block_stmt, ctx),
Statement::IfStatement(if_stmt) => self.try_fold_if(if_stmt, ctx),
Statement::ForStatement(for_stmt) => self.try_fold_for(for_stmt, ctx),
Statement::ExpressionStatement(expr_stmt) => {
Self::try_fold_expression_stmt(expr_stmt, ctx)
}
Statement::LabeledStatement(labeled) => Self::try_fold_labeled(labeled, ctx),
Statement::BlockStatement(s) => Self::try_optimize_block(s, ctx),
Statement::IfStatement(s) => self.try_fold_if(s, ctx),
Statement::ForStatement(s) => self.try_fold_for(s, ctx),
Statement::ExpressionStatement(s) => Self::try_fold_expression_stmt(s, ctx),
Statement::TryStatement(s) => Self::try_fold_try(s, ctx),
Statement::LabeledStatement(s) => Self::try_fold_labeled(s, ctx),
_ => None,
} {
*stmt = new_stmt;
@ -335,6 +334,29 @@ impl<'a, 'b> PeepholeRemoveDeadCode {
})
}
fn try_fold_try(s: &mut TryStatement<'a>, ctx: Ctx<'a, 'b>) -> Option<Statement<'a>> {
if !s.block.body.is_empty() {
return None;
}
if let Some(finalizer) = &mut s.finalizer {
if finalizer.body.is_empty() {
Some(ctx.ast.statement_empty(s.span))
} else {
let mut block = ctx.ast.block_statement(SPAN, ctx.ast.vec());
std::mem::swap(&mut **finalizer, &mut block);
Some(Statement::BlockStatement(ctx.ast.alloc(block)))
}
} else {
if let Some(handler) = &s.handler {
if handler.body.body.iter().any(|s| matches!(s, Statement::VariableDeclaration(_)))
{
return None;
}
}
Some(ctx.ast.statement_empty(s.span))
}
}
// `([1,2,3, foo()])` -> `foo()`
fn try_fold_array_expression(
array_expr: &mut ArrayExpression<'a>,
@ -670,4 +692,19 @@ mod test {
fold_same("(0, o.f)();");
fold("var obj = Object((null, 2, 3), 1, 2);", "var obj = Object(3, 1, 2);");
}
#[test]
fn test_fold_try_statement() {
fold_same("try { throw 0 } catch (e) { foo() }");
fold_same("try {} catch (e) { var foo }");
fold("try {} catch (e) { foo() }", "");
fold("try {} catch (e) { foo() } finally {}", "");
fold("try {} finally { foo() }", "{ foo() }");
fold("try {} catch (e) { foo() } finally { bar() }", "{ bar() }");
fold("try {} finally { var x = foo() }", "{ var x = foo() }");
fold("try {} catch (e) { foo() } finally { var x = bar() }", "{ var x = bar() }");
fold("try {} finally { let x = foo() }", "{ let x = foo() }");
fold("try {} catch (e) { foo() } finally { let x = bar() }", "{ let x = bar();}");
fold("try {} catch () { } finally {}", "");
}
}