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feat(minifier): fold BigInt(1n) -> 1n #8270

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graphite-app merged 1 commit into from
Jan 6, 2025
Merged

feat(minifier): fold BigInt(1n) -> 1n #8270

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149 changes: 86 additions & 63 deletions crates/oxc_minifier/src/ast_passes/peephole_substitute_alternate_syntax.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -650,69 +650,86 @@ impl<'a, 'b> PeepholeSubstituteAlternateSyntax {
}
}

/// Fold `Boolean`, `Number`, `String`, `BigInt` constructors.
fn try_fold_simple_function_call(
call_expr: &mut CallExpression<'a>,
ctx: Ctx<'a, 'b>,
) -> Option<Expression<'a>> {
if call_expr.optional || call_expr.arguments.len() != 1 {
return None;
}
if call_expr.callee.is_global_reference_name("Boolean", ctx.symbols()) {
let Expression::Identifier(ident) = &call_expr.callee else { return None };
let name = ident.name.as_str();
if !matches!(name, "Boolean" | "Number" | "String" | "BigInt") {
return None;
}
let args = &mut call_expr.arguments;
if args.len() != 1 {
return None;
}
let arg = args[0].as_expression_mut()?;
if !ctx.is_global_reference(ident) {
return None;
}
match name {
// `Boolean(a)` -> `!!(a)`
// http://www.ecma-international.org/ecma-262/6.0/index.html#sec-boolean-constructor-boolean-value
// and
// http://www.ecma-international.org/ecma-262/6.0/index.html#sec-logical-not-operator-runtime-semantics-evaluation

let arg = call_expr.arguments.get_mut(0).and_then(|arg| arg.as_expression_mut())?;

if let Expression::UnaryExpression(unary_expr) = arg {
if unary_expr.operator == UnaryOperator::LogicalNot {
return Some(ctx.ast.move_expression(arg));
"Boolean" => {
if let Expression::UnaryExpression(unary_expr) = arg {
if unary_expr.operator == UnaryOperator::LogicalNot {
return Some(ctx.ast.move_expression(arg));
}
}
Some(
ctx.ast.expression_unary(
call_expr.span,
UnaryOperator::LogicalNot,
ctx.ast.expression_unary(
call_expr.span,
UnaryOperator::LogicalNot,
ctx.ast.move_expression(
call_expr
.arguments
.get_mut(0)
.and_then(|arg| arg.as_expression_mut())?,
),
),
),
)
}

Some(ctx.ast.expression_unary(
call_expr.span,
UnaryOperator::LogicalNot,
ctx.ast.expression_unary(
"String" => {
// `String(a)` -> `'' + (a)`
if !matches!(arg, Expression::Identifier(_) | Expression::CallExpression(_))
&& !arg.is_literal()
{
return None;
}
Some(ctx.ast.expression_binary(
call_expr.span,
UnaryOperator::LogicalNot,
ctx.ast.move_expression(
call_expr.arguments.get_mut(0).and_then(|arg| arg.as_expression_mut())?,
),
),
))
} else if call_expr.callee.is_global_reference_name("String", ctx.symbols()) {
// `String(a)` -> `'' + (a)`
let arg = call_expr.arguments.get_mut(0).and_then(|arg| arg.as_expression_mut())?;

if !matches!(arg, Expression::Identifier(_) | Expression::CallExpression(_))
&& !arg.is_literal()
{
return None;
ctx.ast.expression_string_literal(SPAN, "", None),
BinaryOperator::Addition,
ctx.ast.move_expression(arg),
))
}

Some(ctx.ast.expression_binary(
call_expr.span,
ctx.ast.expression_string_literal(SPAN, "", None),
BinaryOperator::Addition,
ctx.ast.move_expression(arg),
))
} else if call_expr.callee.is_global_reference_name("Number", ctx.symbols()) {
let number = call_expr
.arguments
.get_mut(0)
.and_then(|arg| arg.as_expression_mut())?
.to_number()?;

Some(ctx.ast.expression_numeric_literal(
call_expr.span,
number,
None,
NumberBase::Decimal,
))
} else {
None
"Number" => {
let number = arg.to_number()?;
Some(ctx.ast.expression_numeric_literal(
call_expr.span,
number,
None,
NumberBase::Decimal,
))
}
// `BigInt(1n)` -> `1n`
"BigInt" => {
if !matches!(arg, Expression::BigIntLiteral(_)) {
return None;
}
Some(ctx.ast.move_expression(arg))
}
_ => None,
}
}

Expand Down Expand Up @@ -1218,20 +1235,6 @@ mod test {
test_same("goog.bind(f.m).call(g)");
}

#[test]
fn test_simple_function_call1() {
test("var a = String(23)", "var a = '' + 23");
// Don't fold the existence check to preserve behavior
test_same("var a = String?.(23)");

test("var a = String('hello')", "var a = '' + 'hello'");
// Don't fold the existence check to preserve behavior
test_same("var a = String?.('hello')");

test_same("var a = String('hello', bar());");
test_same("var a = String({valueOf: function() { return 1; }});");
}

#[test]
fn test_simple_function_call2() {
test("var a = Boolean(true)", "var a = !0");
Expand Down Expand Up @@ -1424,10 +1427,30 @@ mod test {
}

#[test]
fn test_fold_number_call() {
fn test_fold_string_constructor() {
test("var a = String(23)", "var a = '' + 23");
// Don't fold the existence check to preserve behavior
test_same("var a = String?.(23)");

test("var a = String('hello')", "var a = '' + 'hello'");
// Don't fold the existence check to preserve behavior
test_same("var a = String?.('hello')");

test_same("var a = String('hello', bar());");
test_same("var a = String({valueOf: function() { return 1; }});");
}

#[test]
fn test_fold_number_constructor() {
test("Number(0)", "0");
test("Number(true)", "1");
test("Number(false)", "0");
test("Number('foo')", "NaN");
}

#[test]
fn test_fold_big_int_constructor() {
test("BigInt(1n)", "1n");
test_same("BigInt(1)");
}
}
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