dan/oxc
1
0
Fork 0
mirror of https://github.com/danbulant/oxc synced 2026-05-19 04:08:41 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

refactor(minifier): clean up has_no_side_effect_for_evaluation_same_target (#8675)

Browse source
This commit is contained in:
Boshen 2025-01-23 12:52:48 +00:00 committed by Boshen
parent 3fa87ff6a6
commit 75a579b619
No known key found for this signature in database
GPG key ID: 67715A371E534061
2 changed files with 23 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
crates/oxc_minifier/src/peephole/fold_constants.rs
View file

@ -673,6 +673,7 @@ impl<'a, 'b> PeepholeOptimizations {
| "undefined"
| "object"
| "function"
| "unknown" // IE
) {
return Some(ctx.ast.expression_boolean_literal(
bin_expr.span,
@ -1032,6 +1033,7 @@ mod test {
test("'a' == 'a'", "!0");
test("'b' != 'a'", "!0");
test_same("typeof a != 'number'");
test_same("typeof a != 'unknown'"); // IE
test("'a' === 'a'", "!0");
test("'b' !== 'a'", "!0");
test_same("'' + x <= '' + y");

46
crates/oxc_minifier/src/peephole/minimize_conditions.rs
View file

@ -1075,16 +1075,13 @@ impl<'a> PeepholeOptimizations {
if self.target < ESTarget::ES2020 {
return None;
}
let Expression::AssignmentExpression(assignment_expr) = &mut expr.right else {
return None;
};
if assignment_expr.operator != AssignmentOperator::Assign {
return None;
}
let new_op = expr.operator.to_assignment_operator();
if !Self::has_no_side_effect_for_evaluation_same_target(
&assignment_expr.left,
&expr.left,
@ -1092,7 +1089,6 @@ impl<'a> PeepholeOptimizations {
) {
return None;
}
assignment_expr.span = expr.span;
assignment_expr.operator = new_op;
Some(ctx.ast.move_expression(&mut expr.right))
@ -1129,37 +1125,36 @@ impl<'a> PeepholeOptimizations {
///
/// - `a`, `a`
/// - `a.b`, `a.b`
/// - `a.#b`, `a.#b`
/// - `a["b"]`, `a["b"]`
fn has_no_side_effect_for_evaluation_same_target(
assignment_target: &AssignmentTarget,
expr: &Expression,
ctx: &mut TraverseCtx<'a>,
) -> bool {
match (&assignment_target, &expr) {
(
AssignmentTarget::AssignmentTargetIdentifier(write_id_ref),
Expression::Identifier(read_id_ref),
) => write_id_ref.name == read_id_ref.name,
(
AssignmentTarget::StaticMemberExpression(_),
Expression::StaticMemberExpression(_),
)
| (
AssignmentTarget::PrivateFieldExpression(_),
Expression::PrivateFieldExpression(_),
) => {
let write_expr = assignment_target.to_member_expression();
let read_expr = expr.to_member_expression();
let Expression::Identifier(write_expr_object_id) = &write_expr.object() else {
if let (
AssignmentTarget::AssignmentTargetIdentifier(write_id_ref),
Expression::Identifier(read_id_ref),
) = (assignment_target, expr)
{
return write_id_ref.name == read_id_ref.name;
}
if let Some(write_expr) = assignment_target.as_member_expression() {
if let MemberExpression::ComputedMemberExpression(e) = write_expr {
if !matches!(e.expression, Expression::StringLiteral(_)) {
return false;
};
}
}
let Expression::Identifier(write_expr_object_id) = &write_expr.object() else {
return false;
};
if let Some(read_expr) = expr.as_member_expression() {
// It should also return false when the reference might refer to a reference value created by a with statement
// when the minifier supports with statements
!Ctx(ctx).is_global_reference(write_expr_object_id)
&& write_expr.content_eq(read_expr)
return !Ctx(ctx).is_global_reference(write_expr_object_id)
&& write_expr.content_eq(read_expr);
}
_ => false,
}
false
}
/// Compress `a = a + b` to `a += b`
@ -2475,6 +2470,7 @@ mod test {
// GetValue(x) has no sideeffect when x is a resolved identifier
test("var x; x.y || (x.y = 3)", "var x; x.y ||= 3");
test("var x; x['y'] || (x['y'] = 3)", "var x; x.y ||= 3");
test("var x; x.#y || (x.#y = 3)", "var x; x.#y ||= 3");
test_same("x.y || (x.y = 3)");
// this can be compressed if `y` does not have side effect