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feat(minifier): compress loose equals undefined (#8268)

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camc314 2025-01-06 02:21:28 +00:00
parent f000596edf
commit a4df3874c5
1 changed files with 37 additions and 1 deletions
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38
crates/oxc_minifier/src/ast_passes/peephole_substitute_alternate_syntax.rs
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@ -142,7 +142,8 @@ impl<'a> Traverse<'a> for PeepholeSubstituteAlternateSyntax {
Expression::LogicalExpression(e) => Self::try_compress_is_null_or_undefined(e, ctx),
Expression::NewExpression(e) => Self::try_fold_new_expression(e, ctx),
Expression::TemplateLiteral(t) => Self::try_fold_template_literal(t, ctx),
Expression::BinaryExpression(e) => Self::try_compress_typeof_undefined(e, ctx),
Expression::BinaryExpression(e) => Self::try_fold_loose_equals_undefined(e, ctx)
.or_else(|| Self::try_compress_typeof_undefined(e, ctx)),
Expression::CallExpression(e) => {
Self::try_fold_literal_constructor_call_expression(e, ctx)
.or_else(|| Self::try_fold_simple_function_call(e, ctx))
@ -448,6 +449,32 @@ impl<'a, 'b> PeepholeSubstituteAlternateSyntax {
}
None
}
fn try_fold_loose_equals_undefined(
e: &mut BinaryExpression<'a>,
ctx: Ctx<'a, 'b>,
) -> Option<Expression<'a>> {
// `foo == void 0` -> `foo == null`, `foo == undefined` -> `foo == null`
// `foo != void 0` -> `foo == null`, `foo == undefined` -> `foo == null`
if e.operator == BinaryOperator::Inequality || e.operator == BinaryOperator::Equality {
let (left, right) = if e.right.is_undefined() || e.right.is_void_0() {
(
ctx.ast.move_expression(&mut e.left),
ctx.ast.expression_null_literal(e.right.span()),
)
} else if e.left.is_undefined() || e.left.is_void_0() {
(
ctx.ast.move_expression(&mut e.right),
ctx.ast.expression_null_literal(e.left.span()),
)
} else {
return None;
};
return Some(ctx.ast.expression_binary(e.span, left, e.operator, right));
}
None
}
/// Removes redundant argument of `ReturnStatement`
///
@ -1328,6 +1355,15 @@ mod test {
test_same("foo !== void 0 && bar !== null");
}
#[test]
fn test_fold_loose_equals_undefined() {
test_same("foo != null");
test("foo != undefined", "foo != null");
test("foo != void 0", "foo != null");
test("undefined != foo", "foo != null");
test("void 0 != foo", "foo != null");
}
#[test]
fn test_try_compress_type_of_equal_string() {
test("typeof foo === 'number'", "typeof foo == 'number'");