Skip to content

feat(minifier): compress typeof foo === 'object' && foo !== null to typeof foo == 'object' && !!foo #8638

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
graphite-app merged 1 commit into from
Jan 21, 2025
Merged

feat(minifier): compress typeof foo === 'object' && foo !== null to typeof foo == 'object' && !!foo #8638

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
216 changes: 216 additions & 0 deletions crates/oxc_minifier/src/peephole/substitute_alternate_syntax.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ use oxc_ecmascript::{
};
use oxc_span::cmp::ContentEq;
use oxc_span::GetSpan;
use oxc_span::SPAN;
use oxc_syntax::{
es_target::ESTarget,
identifier::is_identifier_name,
Expand Down Expand Up @@ -134,6 +135,7 @@ impl<'a, 'b> PeepholeOptimizations {
Self::try_compress_assignment_to_update_expression(e, ctx)
}
Expression::LogicalExpression(e) => Self::try_compress_is_null_or_undefined(e, ctx)
.or_else(|| Self::try_compress_is_object_and_not_null(e, ctx))
.or_else(|| self.try_compress_logical_expression_to_assignment_expression(e, ctx))
.or_else(|| Self::try_rotate_logical_expression(e, ctx)),
Expression::TemplateLiteral(t) => Self::try_fold_template_literal(t, ctx),
Expand Down Expand Up @@ -576,6 +578,171 @@ impl<'a, 'b> PeepholeOptimizations {
}
}

/// Compress `typeof foo === 'object' && foo !== null` into `typeof foo == 'object' && !!foo`.
///
/// - `typeof foo === 'object' && foo !== null` => `typeof foo == 'object' && !!foo`
/// - `typeof foo == 'object' && foo != null` => `typeof foo == 'object' && !!foo`
/// - `typeof foo !== 'object' || foo === null` => `typeof foo != 'object' || !foo`
/// - `typeof foo != 'object' || foo == null` => `typeof foo != 'object' || !foo`
///
/// If `typeof foo == 'object'`, then `foo` is guaranteed to be an object or null.
/// - If `foo` is an object, then `foo !== null` is `true`. If `foo` is null, then `foo !== null` is `false`.
/// - If `foo` is an object, then `foo != null` is `true`. If `foo` is null, then `foo != null` is `false`.
/// - If `foo` is an object, then `!!foo` is `true`. If `foo` is null, then `!!foo` is `false`.
///
/// This compression is safe for `document.all` because `typeof document.all` is not `'object'`.
fn try_compress_is_object_and_not_null(
expr: &mut LogicalExpression<'a>,
ctx: Ctx<'a, '_>,
) -> Option<Expression<'a>> {
let inversed = match expr.operator {
LogicalOperator::And => false,
LogicalOperator::Or => true,
LogicalOperator::Coalesce => return None,
};

if let Some(new_expr) = Self::try_compress_is_object_and_not_null_for_left_and_right(
&expr.left,
&expr.right,
expr.span,
ctx,
inversed,
) {
return Some(new_expr);
}

let Expression::LogicalExpression(left) = &mut expr.left else {
return None;
};
let inversed = match expr.operator {
LogicalOperator::And => false,
LogicalOperator::Or => true,
LogicalOperator::Coalesce => return None,
};

Self::try_compress_is_object_and_not_null_for_left_and_right(
&left.right,
&expr.right,
Span::new(left.right.span().start, expr.span.end),
ctx,
inversed,
)
.map(|new_expr| {
ctx.ast.expression_logical(
expr.span,
ctx.ast.move_expression(&mut left.left),
expr.operator,
new_expr,
)
})
}

fn try_compress_is_object_and_not_null_for_left_and_right(
left: &Expression<'a>,
right: &Expression<'a>,
span: Span,
ctx: Ctx<'a, 'b>,
inversed: bool,
) -> Option<Expression<'a>> {
let pair = Self::commutative_pair(
(&left, &right),
|a_expr| {
let Expression::BinaryExpression(a) = a_expr else { return None };
let is_target_ops = if inversed {
matches!(
a.operator,
BinaryOperator::StrictInequality | BinaryOperator::Inequality
)
} else {
matches!(a.operator, BinaryOperator::StrictEquality | BinaryOperator::Equality)
};
if !is_target_ops {
return None;
}
let (id, ()) = Self::commutative_pair(
(&a.left, &a.right),
|a_a| {
let Expression::UnaryExpression(a_a) = a_a else { return None };
if a_a.operator != UnaryOperator::Typeof {
return None;
}
let Expression::Identifier(id) = &a_a.argument else { return None };
Some(id)
},
|b| b.is_specific_string_literal("object").then_some(()),
)?;
Some((id, a_expr))
},
|b| {
let Expression::BinaryExpression(b) = b else {
return None;
};
let is_target_ops = if inversed {
matches!(b.operator, BinaryOperator::StrictEquality | BinaryOperator::Equality)
} else {
matches!(
b.operator,
BinaryOperator::StrictInequality | BinaryOperator::Inequality
)
};
if !is_target_ops {
return None;
}
let (id, ()) = Self::commutative_pair(
(&b.left, &b.right),
|a_a| {
let Expression::Identifier(id) = a_a else { return None };
Some(id)
},
|b| b.is_null().then_some(()),
)?;
Some(id)
},
);
let ((typeof_id_ref, typeof_binary_expr), is_null_id_ref) = pair?;
if typeof_id_ref.name != is_null_id_ref.name {
return None;
}
// It should also return None when the reference might refer to a reference value created by a with statement
// when the minifier supports with statements
if ctx.is_global_reference(typeof_id_ref) {
return None;
}

let mut new_left_expr = typeof_binary_expr.clone_in(ctx.ast.allocator);
if let Expression::BinaryExpression(new_left_expr_binary) = &mut new_left_expr {
new_left_expr_binary.operator =
if inversed { BinaryOperator::Inequality } else { BinaryOperator::Equality };
} else {
unreachable!();
}

let new_right_expr = if inversed {
ctx.ast.expression_unary(
SPAN,
UnaryOperator::LogicalNot,
ctx.ast.expression_identifier_reference(is_null_id_ref.span, is_null_id_ref.name),
)
} else {
ctx.ast.expression_unary(
SPAN,
UnaryOperator::LogicalNot,
ctx.ast.expression_unary(
SPAN,
UnaryOperator::LogicalNot,
ctx.ast
.expression_identifier_reference(is_null_id_ref.span, is_null_id_ref.name),
),
)
};
Some(ctx.ast.expression_logical(
span,
new_left_expr,
if inversed { LogicalOperator::Or } else { LogicalOperator::And },
new_right_expr,
))
}

fn commutative_pair<'x, A, F, G, RetF: 'x, RetG: 'x>(
pair: (&'x A, &'x A),
check_a: F,
Expand Down Expand Up @@ -1838,6 +2005,55 @@ mod test {
test_same("(_foo = foo) === void 0 || bar === null");
}

#[test]
fn test_fold_is_object_and_not_null() {
test(
"var foo; v = typeof foo === 'object' && foo !== null",
"var foo; v = typeof foo == 'object' && !!foo",
);
test(
"var foo; v = typeof foo == 'object' && foo !== null",
"var foo; v = typeof foo == 'object' && !!foo",
);
test(
"var foo; v = typeof foo === 'object' && foo != null",
"var foo; v = typeof foo == 'object' && !!foo",
);
test(
"var foo; v = typeof foo == 'object' && foo != null",
"var foo; v = typeof foo == 'object' && !!foo",
);
test(
"var foo; v = typeof foo !== 'object' || foo === null",
"var foo; v = typeof foo != 'object' || !foo",
);
test(
"var foo; v = typeof foo != 'object' || foo === null",
"var foo; v = typeof foo != 'object' || !foo",
);
test(
"var foo; v = typeof foo !== 'object' || foo == null",
"var foo; v = typeof foo != 'object' || !foo",
);
test(
"var foo; v = typeof foo != 'object' || foo == null",
"var foo; v = typeof foo != 'object' || !foo",
);
test(
"var foo, bar; v = typeof foo === 'object' && foo !== null && bar !== 1",
"var foo, bar; v = typeof foo == 'object' && !!foo && bar !== 1",
);
test(
"var foo, bar; v = bar !== 1 && typeof foo === 'object' && foo !== null",
"var foo, bar; v = bar !== 1 && typeof foo == 'object' && !!foo",
);
test_same("var foo; v = typeof foo.a == 'object' && foo.a !== null"); // cannot be folded because accessing foo.a might have a side effect
test_same("v = foo !== null && typeof foo == 'object'"); // cannot be folded because accessing foo might have a side effect
test_same("v = typeof foo == 'object' && foo !== null"); // cannot be folded because accessing foo might have a side effect
test_same("var foo, bar; v = typeof foo == 'object' && bar !== null");
test_same("var foo; v = typeof foo == 'string' && foo !== null");
}

#[test]
fn test_fold_logical_expression_to_assignment_expression() {
test("x || (x = 3)", "x ||= 3");
Expand Down
16 changes: 8 additions & 8 deletions tasks/minsize/minsize.snap
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,27 +1,27 @@
| Oxc | ESBuild | Oxc | ESBuild |
Original | minified | minified | gzip | gzip | Fixture
-------------------------------------------------------------------------------------
72.14 kB | 23.70 kB | 23.70 kB | 8.60 kB | 8.54 kB | react.development.js
72.14 kB | 23.67 kB | 23.70 kB | 8.60 kB | 8.54 kB | react.development.js

173.90 kB | 59.79 kB | 59.82 kB | 19.41 kB | 19.33 kB | moment.js

287.63 kB | 90.08 kB | 90.07 kB | 32.03 kB | 31.95 kB | jquery.js
287.63 kB | 90.08 kB | 90.07 kB | 32.02 kB | 31.95 kB | jquery.js

342.15 kB | 118.19 kB | 118.14 kB | 44.45 kB | 44.37 kB | vue.js

544.10 kB | 71.76 kB | 72.48 kB | 26.15 kB | 26.20 kB | lodash.js
544.10 kB | 71.75 kB | 72.48 kB | 26.15 kB | 26.20 kB | lodash.js

555.77 kB | 272.90 kB | 270.13 kB | 90.90 kB | 90.80 kB | d3.js
555.77 kB | 272.89 kB | 270.13 kB | 90.90 kB | 90.80 kB | d3.js

1.01 MB | 460.18 kB | 458.89 kB | 126.78 kB | 126.71 kB | bundle.min.js
1.01 MB | 460.18 kB | 458.89 kB | 126.77 kB | 126.71 kB | bundle.min.js

1.25 MB | 652.90 kB | 646.76 kB | 163.54 kB | 163.73 kB | three.js

2.14 MB | 724.06 kB | 724.14 kB | 179.94 kB | 181.07 kB | victory.js
2.14 MB | 724.01 kB | 724.14 kB | 179.94 kB | 181.07 kB | victory.js

3.20 MB | 1.01 MB | 1.01 MB | 332.00 kB | 331.56 kB | echarts.js
3.20 MB | 1.01 MB | 1.01 MB | 332.01 kB | 331.56 kB | echarts.js

6.69 MB | 2.31 MB | 2.31 MB | 491.99 kB | 488.28 kB | antd.js

10.95 MB | 3.48 MB | 3.49 MB | 905.39 kB | 915.50 kB | typescript.js
10.95 MB | 3.48 MB | 3.49 MB | 905.37 kB | 915.50 kB | typescript.js

Loading