Skip to content

Commit

Permalink
feat(minifier): implement folding of simple function calls (String) (
Browse files Browse the repository at this point in the history
…#6483)

basically `String(foo)` -> `foo + ''`
  • Loading branch information
camc314 committed Oct 13, 2024
1 parent 58467a5 commit 0c91064
Show file tree
Hide file tree
Showing 2 changed files with 42 additions and 6 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -96,7 +96,13 @@ impl<'a> Traverse<'a> for PeepholeSubstituteAlternateSyntax {
}
}
Expression::CallExpression(call_expr) => {
if let Some(call_expr) = Self::try_fold_call_expression(call_expr, ctx) {
if let Some(call_expr) =
Self::try_fold_literal_constructor_call_expression(call_expr, ctx)
{
*expr = call_expr;
self.changed = true;
} else if let Some(call_expr) = Self::try_fold_simple_function_call(call_expr, ctx)
{
*expr = call_expr;
self.changed = true;
}
Expand Down Expand Up @@ -398,7 +404,7 @@ impl<'a> PeepholeSubstituteAlternateSyntax {
}
}

fn try_fold_call_expression(
fn try_fold_literal_constructor_call_expression(
call_expr: &mut CallExpression<'a>,
ctx: &mut TraverseCtx<'a>,
) -> Option<Expression<'a>> {
Expand Down Expand Up @@ -452,6 +458,37 @@ impl<'a> PeepholeSubstituteAlternateSyntax {
}
}

fn try_fold_simple_function_call(
call_expr: &mut CallExpression<'a>,
ctx: &mut TraverseCtx<'a>,
) -> 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()) {
// TODO
None
} 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;
}

Some(ctx.ast.expression_binary(
call_expr.span,
ctx.ast.expression_from_string_literal(ctx.ast.string_literal(SPAN, "")),
BinaryOperator::Addition,
ctx.ast.move_expression(arg),
))
} else {
None
}
}

fn try_fold_chain_call_expression(
&mut self,
call_expr: &mut CallExpression<'a>,
Expand Down Expand Up @@ -830,7 +867,6 @@ mod test {
}

#[test]
#[ignore]
fn test_simple_function_call1() {
test("var a = String(23)", "var a = '' + 23");
// 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 @@ -6,15 +6,15 @@ Original | Minified | esbuild | Gzip | esbuild

287.63 kB | 92.83 kB | 90.07 kB | 32.29 kB | 31.95 kB | jquery.js

342.15 kB | 124.11 kB | 118.14 kB | 44.80 kB | 44.37 kB | vue.js
342.15 kB | 124.06 kB | 118.14 kB | 44.79 kB | 44.37 kB | vue.js

544.10 kB | 74.13 kB | 72.48 kB | 26.23 kB | 26.20 kB | lodash.js

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

1.01 MB | 470.11 kB | 458.89 kB | 126.97 kB | 126.71 kB | bundle.min.js
1.01 MB | 470.08 kB | 458.89 kB | 126.96 kB | 126.71 kB | bundle.min.js

1.25 MB | 670.96 kB | 646.76 kB | 164.72 kB | 163.73 kB | three.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

Expand Down

0 comments on commit 0c91064

Please sign in to comment.