From 5ed439bcaff16a9023ba39afefa19e0fa5818835 Mon Sep 17 00:00:00 2001
From: camc314 <18101008+camc314@users.noreply.github.com>
Date: Mon, 6 Jan 2025 23:26:19 +0000
Subject: [PATCH] feat(minifier): minify typeof in binary expressions (#8302)
---
.../src/ast_passes/peephole_fold_constants.rs | 63 +++++++++++++++++--
tasks/minsize/minsize.snap | 2 +-
2 files changed, 60 insertions(+), 5 deletions(-)
diff --git a/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs b/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs
index 081d4826981f3..1827cb3cdeeb6 100644
--- a/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs
+++ b/crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs
@@ -31,7 +31,8 @@ impl<'a> Traverse<'a> for PeepholeFoldConstants {
fn exit_expression(&mut self, expr: &mut Expression<'a>, ctx: &mut TraverseCtx<'a>) {
let ctx = Ctx(ctx);
if let Some(folded_expr) = match expr {
- Expression::BinaryExpression(e) => Self::try_fold_binary_expr(e, ctx),
+ Expression::BinaryExpression(e) => Self::try_fold_binary_expr(e, ctx)
+ .or_else(|| Self::try_fold_binary_typeof_comparison(e, ctx)),
Expression::UnaryExpression(e) => Self::try_fold_unary_expr(e, ctx),
Expression::StaticMemberExpression(e) => Self::try_fold_static_member_expr(e, ctx),
Expression::LogicalExpression(e) => Self::try_fold_logical_expr(e, ctx),
@@ -624,6 +625,55 @@ impl<'a, 'b> PeepholeFoldConstants {
.to_js_string()
.map(|value| ctx.ast.expression_string_literal(object.span(), value, None))
}
+
+ // `typeof a === typeof b` -> `typeof a == typeof b`, `typeof a != typeof b` -> `typeof a != typeof b`,
+ // `typeof a == typeof a` -> `true`, `typeof a != typeof a` -> `false`
+ fn try_fold_binary_typeof_comparison(
+ bin_expr: &mut BinaryExpression<'a>,
+ ctx: Ctx<'a, 'b>,
+ ) -> Option<Expression<'a>> {
+ if bin_expr.operator.is_equality() {
+ if let (Expression::UnaryExpression(left), Expression::UnaryExpression(right)) =
+ (&bin_expr.left, &bin_expr.right)
+ {
+ if left.operator.is_typeof() && right.operator.is_typeof() {
+ if let (
+ Expression::Identifier(left_ident),
+ Expression::Identifier(right_ident),
+ ) = (&left.argument, &right.argument)
+ {
+ if left_ident.name == right_ident.name {
+ return Some(ctx.ast.expression_boolean_literal(
+ bin_expr.span,
+ matches!(
+ bin_expr.operator,
+ BinaryOperator::StrictEquality | BinaryOperator::Equality
+ ),
+ ));
+ }
+ }
+
+ if matches!(
+ bin_expr.operator,
+ BinaryOperator::StrictEquality | BinaryOperator::StrictInequality
+ ) {
+ return Some(ctx.ast.expression_binary(
+ bin_expr.span,
+ ctx.ast.move_expression(&mut bin_expr.left),
+ if bin_expr.operator == BinaryOperator::StrictEquality {
+ BinaryOperator::Equality
+ } else {
+ BinaryOperator::Inequality
+ },
+ ctx.ast.move_expression(&mut bin_expr.right),
+ ));
+ }
+ }
+ }
+ }
+
+ None
+ }
}
/// <https://github.com/google/closure-compiler/blob/v20240609/test/com/google/javascript/jscomp/PeepholeFoldConstantsTest.java>
@@ -931,11 +981,8 @@ mod test {
test("'a' == 'a'", "true");
test("'b' != 'a'", "true");
test_same("typeof a != 'number'");
- test_same("typeof a == typeof a");
test("'a' === 'a'", "true");
test("'b' !== 'a'", "true");
- test_same("typeof a === typeof a");
- test_same("typeof a !== typeof a");
test_same("'' + x <= '' + y");
test_same("'' + x != '' + y");
test_same("'' + x === '' + y");
@@ -1797,4 +1844,12 @@ mod test {
test("typeof foo + ''", "typeof foo");
test_same("typeof foo - ''");
}
+
+ #[test]
+ fn test_fold_same_typeof() {
+ test("typeof foo === typeof bar", "typeof foo == typeof bar");
+ test("typeof foo !== typeof bar", "typeof foo != typeof bar");
+ test("typeof foo.bar === typeof foo.bar", "typeof foo.bar == typeof foo.bar");
+ test("typeof foo.bar !== typeof foo.bar", "typeof foo.bar != typeof foo.bar");
+ }
}
diff --git a/tasks/minsize/minsize.snap b/tasks/minsize/minsize.snap
index f78847f3d6fca..084a421f0306e 100644
--- a/tasks/minsize/minsize.snap
+++ b/tasks/minsize/minsize.snap
@@ -13,7 +13,7 @@ Original | minified | minified | gzip | gzip | Fixture
555.77 kB | 273.15 kB | 270.13 kB | 90.95 kB | 90.80 kB | d3.js
-1.01 MB | 460.32 kB | 458.89 kB | 126.84 kB | 126.71 kB | bundle.min.js
+1.01 MB | 460.31 kB | 458.89 kB | 126.84 kB | 126.71 kB | bundle.min.js
1.25 MB | 652.68 kB | 646.76 kB | 163.53 kB | 163.73 kB | three.js