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feat(minifier): a != null ? a : b -> a ?? b (#8352)
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@camc314
camc314 committed Jan 9, 2025
1 parent 1c4658d commit 793cb43
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Showing 4 changed files with 60 additions and 20 deletions.
5 changes: 3 additions & 2 deletions crates/oxc_minifier/src/ast_passes/mod.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
use oxc_allocator::Vec;
use oxc_ast::ast::*;
use oxc_syntax::es_target::ESTarget;
use oxc_traverse::{traverse_mut_with_ctx, ReusableTraverseCtx, Traverse, TraverseCtx};

mod collapse_variable_declarations;
Expand Down Expand Up @@ -53,15 +54,15 @@ pub struct PeepholeOptimizations {
impl PeepholeOptimizations {
/// `in_fixed_loop`: Do not compress syntaxes that are hard to analyze inside the fixed loop.
/// Opposite of `late` in Closure Compiler.
pub fn new(in_fixed_loop: bool, options: CompressOptions) -> Self {
pub fn new(target: ESTarget, in_fixed_loop: bool, options: CompressOptions) -> Self {
Self {
x0_statement_fusion: StatementFusion::new(),
x1_minimize_exit_points: MinimizeExitPoints::new(),
x2_exploit_assigns: ExploitAssigns::new(),
x3_collapse_variable_declarations: CollapseVariableDeclarations::new(),
x4_peephole_fold_constants: PeepholeFoldConstants::new(),
x5_peephole_remove_dead_code: PeepholeRemoveDeadCode::new(),
x6_peephole_minimize_conditions: PeepholeMinimizeConditions::new(),
x6_peephole_minimize_conditions: PeepholeMinimizeConditions::new(target),
x7_peephole_replace_known_methods: PeepholeReplaceKnownMethods::new(),
x8_convert_to_dotted_properties: ConvertToDottedProperties::new(in_fixed_loop),
x9_peephole_substitute_alternate_syntax: PeepholeSubstituteAlternateSyntax::new(
Expand Down
49 changes: 43 additions & 6 deletions crates/oxc_minifier/src/ast_passes/peephole_minimize_conditions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ use oxc_allocator::Vec;
use oxc_ast::{ast::*, NONE};
use oxc_ecmascript::constant_evaluation::ValueType;
use oxc_span::{cmp::ContentEq, GetSpan, SPAN};
use oxc_syntax::es_target::ESTarget;
use oxc_traverse::{traverse_mut_with_ctx, Ancestor, ReusableTraverseCtx, Traverse, TraverseCtx};

use crate::CompressorPass;
Expand All @@ -14,6 +15,7 @@ use crate::CompressorPass;
///
/// <https://github.com/google/closure-compiler/blob/v20240609/src/com/google/javascript/jscomp/PeepholeMinimizeConditions.java>
pub struct PeepholeMinimizeConditions {
target: ESTarget,
pub(crate) changed: bool,
}

Expand Down Expand Up @@ -56,7 +58,7 @@ impl<'a> Traverse<'a> for PeepholeMinimizeConditions {
Expression::UnaryExpression(e) => Self::try_minimize_not(e, ctx),
Expression::LogicalExpression(e) => Self::try_minimize_logical(e, ctx),
Expression::BinaryExpression(e) => Self::try_minimize_binary(e, ctx),
Expression::ConditionalExpression(e) => Self::try_minimize_conditional(e, ctx),
Expression::ConditionalExpression(e) => self.try_minimize_conditional(e, ctx),
_ => None,
} {
*expr = folded_expr;
Expand All @@ -66,8 +68,8 @@ impl<'a> Traverse<'a> for PeepholeMinimizeConditions {
}

impl<'a> PeepholeMinimizeConditions {
pub fn new() -> Self {
Self { changed: false }
pub fn new(target: ESTarget) -> Self {
Self { target, changed: false }
}

/// Try to minimize NOT nodes such as `!(x==y)`.
Expand Down Expand Up @@ -344,6 +346,7 @@ impl<'a> PeepholeMinimizeConditions {

// based on https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/internal/js_ast/js_ast_helpers.go#L2745
fn try_minimize_conditional(
&self,
expr: &mut ConditionalExpression<'a>,
ctx: &mut TraverseCtx<'a>,
) -> Option<Expression<'a>> {
Expand Down Expand Up @@ -633,7 +636,39 @@ impl<'a> PeepholeMinimizeConditions {
}
}

// TODO: Try using the "??" or "?." operators
// Try using the "??" or "?." operators
if let Expression::BinaryExpression(bin_expr) = &mut expr.test {
if bin_expr.operator == BinaryOperator::Equality
|| bin_expr.operator == BinaryOperator::Inequality
{
if let Some(check) = {
if bin_expr.left.is_null() {
Some(&bin_expr.right)
} else {
Some(&bin_expr.left)
}
} {
// `a != null ? a : b` -> `a ?? b``
if check.content_eq(if bin_expr.operator == BinaryOperator::Equality {
&expr.alternate
} else {
&expr.consequent
}) && self.target >= ESTarget::ES2020
// TODO: this is probably a but too aggressive
&& matches!(check, Expression::Identifier(_))
{
return Some(ctx.ast.expression_logical(
SPAN,
ctx.ast.move_expression(&mut expr.consequent),
LogicalOperator::Coalesce,
ctx.ast.move_expression(&mut expr.alternate),
));
}

// TODO: `a != null ? a.b.c[d](e) : undefined` -> `a?.b.c[d](e)``
}
}
}

// Non esbuild optimizations

Expand Down Expand Up @@ -812,12 +847,13 @@ impl<'a> PeepholeMinimizeConditions {
#[cfg(test)]
mod test {
use oxc_allocator::Allocator;
use oxc_syntax::es_target::ESTarget;

use crate::tester;

fn test(source_text: &str, positive: &str) {
let allocator = Allocator::default();
let mut pass = super::PeepholeMinimizeConditions::new();
let mut pass = super::PeepholeMinimizeConditions::new(ESTarget::ES2025);
tester::test(&allocator, source_text, positive, &mut pass);
}

Expand Down Expand Up @@ -2003,7 +2039,8 @@ mod test {
test("var a; a ? b(c, d) : b(e, d)", "var a; b(a ? c : e, d)");
test("var a; a ? b(...c) : b(...e)", "var a; b(...a ? c : e)");
test("var a; a ? b(c) : b(e)", "var a; b(a ? c : e)");
// test("a != null ? a : b", "a ?? b");
test("a != null ? a : b", "a ?? b");
test_same("a() != null ? a() : b");
// test("a != null ? a.b.c[d](e) : undefined", "a?.b.c[d](e)");
}
}
6 changes: 4 additions & 2 deletions crates/oxc_minifier/src/compressor.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -34,8 +34,10 @@ impl<'a> Compressor<'a> {
RemoveSyntax::new(self.options).build(program, &mut ctx);
// RemoveUnusedCode::new(self.options).build(program, &mut ctx);
Normalize::new().build(program, &mut ctx);
PeepholeOptimizations::new(true, self.options).run_in_loop(program, &mut ctx);
PeepholeOptimizations::new(false, self.options).build(program, &mut ctx);
PeepholeOptimizations::new(self.options.target, true, self.options)
.run_in_loop(program, &mut ctx);
PeepholeOptimizations::new(self.options.target, false, self.options)
.build(program, &mut ctx);
}

pub fn dead_code_elimination(self, program: &mut Program<'a>) {
Expand Down
20 changes: 10 additions & 10 deletions tasks/minsize/minsize.snap
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Original file line number Diff line number Diff line change
Expand Up @@ -3,25 +3,25 @@ Original | minified | minified | gzip | gzip | Fixture
-------------------------------------------------------------------------------------
72.14 kB | 23.70 kB | 23.70 kB | 8.61 kB | 8.54 kB | react.development.js

173.90 kB | 59.79 kB | 59.82 kB | 19.40 kB | 19.33 kB | moment.js
173.90 kB | 59.77 kB | 59.82 kB | 19.39 kB | 19.33 kB | moment.js

287.63 kB | 90.08 kB | 90.07 kB | 32.02 kB | 31.95 kB | jquery.js
287.63 kB | 90.02 kB | 90.07 kB | 32.01 kB | 31.95 kB | jquery.js

342.15 kB | 118.09 kB | 118.14 kB | 44.43 kB | 44.37 kB | vue.js
342.15 kB | 118.08 kB | 118.14 kB | 44.43 kB | 44.37 kB | vue.js

544.10 kB | 71.74 kB | 72.48 kB | 26.14 kB | 26.20 kB | lodash.js
544.10 kB | 71.72 kB | 72.48 kB | 26.15 kB | 26.20 kB | lodash.js

555.77 kB | 273.19 kB | 270.13 kB | 90.91 kB | 90.80 kB | d3.js
555.77 kB | 272.89 kB | 270.13 kB | 90.85 kB | 90.80 kB | d3.js

1.01 MB | 460.17 kB | 458.89 kB | 126.75 kB | 126.71 kB | bundle.min.js
1.01 MB | 460.13 kB | 458.89 kB | 126.74 kB | 126.71 kB | bundle.min.js

1.25 MB | 652.81 kB | 646.76 kB | 163.50 kB | 163.73 kB | three.js

2.14 MB | 726.23 kB | 724.14 kB | 180.12 kB | 181.07 kB | victory.js
2.14 MB | 725.99 kB | 724.14 kB | 180.05 kB | 181.07 kB | victory.js

3.20 MB | 1.01 MB | 1.01 MB | 331.78 kB | 331.56 kB | echarts.js
3.20 MB | 1.01 MB | 1.01 MB | 331.68 kB | 331.56 kB | echarts.js

6.69 MB | 2.32 MB | 2.31 MB | 492.64 kB | 488.28 kB | antd.js
6.69 MB | 2.32 MB | 2.31 MB | 492.60 kB | 488.28 kB | antd.js

10.95 MB | 3.49 MB | 3.49 MB | 907.46 kB | 915.50 kB | typescript.js
10.95 MB | 3.49 MB | 3.49 MB | 907.25 kB | 915.50 kB | typescript.js

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