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feat(minifier): implement folding of simple function calls (Boolean) (
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#6484)

Basically `Boolean(true)` -> `true` or `Boolean(foo)` -> `!!foo`
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camc314 committed Oct 13, 2024
1 parent 0c91064 commit 29ce929
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Showing 2 changed files with 27 additions and 6 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -466,8 +466,30 @@ impl<'a> PeepholeSubstituteAlternateSyntax {
return None;
}
if call_expr.callee.is_global_reference_name("Boolean", ctx.symbols()) {
// TODO
None
// `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));
}
}

Some(ctx.ast.expression_from_unary(ctx.ast.unary_expression(
call_expr.span,
UnaryOperator::LogicalNot,
ctx.ast.expression_from_unary(ctx.ast.unary_expression(
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())?;
Expand Down Expand Up @@ -881,7 +903,6 @@ mod test {
}

#[test]
#[ignore]
fn test_simple_function_call2() {
test("var a = Boolean(true)", "var a = !0");
// Don't fold the existence check to preserve behavior
Expand Down
6 changes: 3 additions & 3 deletions tasks/minsize/minsize.snap
Original file line number Diff line number Diff line change
Expand Up @@ -12,15 +12,15 @@ Original | Minified | esbuild | Gzip | esbuild

555.77 kB | 278.22 kB | 270.13 kB | 91.36 kB | 90.80 kB | d3.js

1.01 MB | 470.08 kB | 458.89 kB | 126.96 kB | 126.71 kB | bundle.min.js
1.01 MB | 470.07 kB | 458.89 kB | 126.95 kB | 126.71 kB | bundle.min.js

1.25 MB | 670.94 kB | 646.76 kB | 164.72 kB | 163.73 kB | three.js

2.14 MB | 756.32 kB | 724.14 kB | 182.74 kB | 181.07 kB | victory.js
2.14 MB | 756.31 kB | 724.14 kB | 182.74 kB | 181.07 kB | victory.js

3.20 MB | 1.05 MB | 1.01 MB | 334.08 kB | 331.56 kB | echarts.js

6.69 MB | 2.44 MB | 2.31 MB | 498.88 kB | 488.28 kB | antd.js
6.69 MB | 2.44 MB | 2.31 MB | 498.86 kB | 488.28 kB | antd.js

10.95 MB | 3.59 MB | 3.49 MB | 913.91 kB | 915.50 kB | typescript.js

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