feat(es/transformer): Merge logical_assignment_operators (#11369)

kdy1 · claude · web-flow · commit 94946fa40b97 · 2025-12-13T14:53:01.000+09:00
Co-authored-by: Claude &lt;noreply@anthropic.com&gt;
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/crates/swc/tests/fixture/issues-7xxx/7064/case1/output/index.js b/crates/swc/tests/fixture/issues-7xxx/7064/case1/output/index.js
@@ -1,7 +1,7 @@
 "use strict";
 function method() {
-    var _obj;
     const obj = {};
+    var _obj;
     (_obj = obj).prop ?? (_obj.prop = "x".repeat(10000000));
 }
 method(); // the large string should be eventually GCed along with the large string, but it will never happen in SWC+es2020
diff --git a/crates/swc/tests/tsc-references/logicalAssignment10(target=es2015).1.normal.js b/crates/swc/tests/tsc-references/logicalAssignment10(target=es2015).1.normal.js
@@ -1,5 +1,4 @@
 //// [logicalAssignment10.ts]
-var _obj, _incr, _oobj_obj, _incr1;
 var count = 0;
 var obj = {};
 function incr() {
@@ -8,7 +7,11 @@ function incr() {
 const oobj = {
     obj
 };
+var _obj;
+var _incr;
 var _;
 (_ = (_obj = obj)[_incr = incr()]) !== null && _ !== void 0 ? _ : _obj[_incr] = incr();
+var _oobj_obj;
+var _incr1;
 var _1;
 (_1 = (_oobj_obj = oobj["obj"])[_incr1 = incr()]) !== null && _1 !== void 0 ? _1 : _oobj_obj[_incr1] = incr();
diff --git a/crates/swc/tests/tsc-references/logicalAssignment10(target=es2020).1.normal.js b/crates/swc/tests/tsc-references/logicalAssignment10(target=es2020).1.normal.js
@@ -1,5 +1,4 @@
 //// [logicalAssignment10.ts]
-var _obj, _incr, _oobj_obj, _incr1;
 var count = 0;
 var obj = {};
 function incr() {
@@ -8,5 +7,9 @@ function incr() {
 const oobj = {
     obj
 };
+var _obj;
+var _incr;
 (_obj = obj)[_incr = incr()] ?? (_obj[_incr] = incr());
+var _oobj_obj;
+var _incr1;
 (_oobj_obj = oobj["obj"])[_incr1 = incr()] ?? (_oobj_obj[_incr1] = incr());
diff --git a/crates/swc/tests/tsc-references/logicalAssignment2(target=es2015).1.normal.js b/crates/swc/tests/tsc-references/logicalAssignment2(target=es2015).1.normal.js
@@ -1,14 +1,25 @@
 //// [logicalAssignment2.ts]
-var _a, _b, _c, _a_foo, _baz, _b_foo, _baz1, _c_foo, _baz2, _a_foo_bar, _b_foo_bar, _c_foo_bar;
+var _a;
 (_a = a).baz && (_a.baz = result.baz);
+var _b;
 (_b = b).baz || (_b.baz = result.baz);
+var _c;
+var _baz;
+(_baz = (_c = c).baz) !== null && _baz !== void 0 ? _baz : _c.baz = result.baz;
+var _a_foo;
+var _baz1;
+(_a_foo = a.foo)[_baz1 = "baz"] && (_a_foo[_baz1] = result.foo.baz);
+var _b_foo;
+var _baz2;
+(_b_foo = b.foo)[_baz2 = "baz"] || (_b_foo[_baz2] = result.foo.baz);
+var _c_foo;
 var _baz3;
-(_baz3 = (_c = c).baz) !== null && _baz3 !== void 0 ? _baz3 : _c.baz = result.baz;
-(_a_foo = a.foo)[_baz = "baz"] && (_a_foo[_baz] = result.foo.baz);
-(_b_foo = b.foo)[_baz1 = "baz"] || (_b_foo[_baz1] = result.foo.baz);
 var _;
-(_ = (_c_foo = c.foo)[_baz2 = "baz"]) !== null && _ !== void 0 ? _ : _c_foo[_baz2] = result.foo.baz;
+(_ = (_c_foo = c.foo)[_baz3 = "baz"]) !== null && _ !== void 0 ? _ : _c_foo[_baz3] = result.foo.baz;
+var _a_foo_bar;
 (_a_foo_bar = a.foo.bar()).baz && (_a_foo_bar.baz = result.foo.bar().baz);
+var _b_foo_bar;
 (_b_foo_bar = b.foo.bar()).baz || (_b_foo_bar.baz = result.foo.bar().baz);
+var _c_foo_bar;
 var _baz4;
 (_baz4 = (_c_foo_bar = c.foo.bar()).baz) !== null && _baz4 !== void 0 ? _baz4 : _c_foo_bar.baz = result.foo.bar().baz;
diff --git a/crates/swc/tests/tsc-references/logicalAssignment2(target=es2020).1.normal.js b/crates/swc/tests/tsc-references/logicalAssignment2(target=es2020).1.normal.js
@@ -1,11 +1,22 @@
 //// [logicalAssignment2.ts]
-var _a, _b, _c, _a_foo, _baz, _b_foo, _baz1, _c_foo, _baz2, _a_foo_bar, _b_foo_bar, _c_foo_bar;
+var _a;
 (_a = a).baz && (_a.baz = result.baz);
+var _b;
 (_b = b).baz || (_b.baz = result.baz);
+var _c;
 (_c = c).baz ?? (_c.baz = result.baz);
+var _a_foo;
+var _baz;
 (_a_foo = a.foo)[_baz = "baz"] && (_a_foo[_baz] = result.foo.baz);
+var _b_foo;
+var _baz1;
 (_b_foo = b.foo)[_baz1 = "baz"] || (_b_foo[_baz1] = result.foo.baz);
+var _c_foo;
+var _baz2;
 (_c_foo = c.foo)[_baz2 = "baz"] ?? (_c_foo[_baz2] = result.foo.baz);
+var _a_foo_bar;
 (_a_foo_bar = a.foo.bar()).baz && (_a_foo_bar.baz = result.foo.bar().baz);
+var _b_foo_bar;
 (_b_foo_bar = b.foo.bar()).baz || (_b_foo_bar.baz = result.foo.bar().baz);
+var _c_foo_bar;
 (_c_foo_bar = c.foo.bar()).baz ?? (_c_foo_bar.baz = result.foo.bar().baz);
diff --git a/crates/swc/tests/tsc-references/logicalAssignment3(target=es2015).1.normal.js b/crates/swc/tests/tsc-references/logicalAssignment3(target=es2015).1.normal.js
@@ -1,6 +1,8 @@
 //// [logicalAssignment3.ts]
-var _a, _b, _c;
+var _a;
 (_a = a).baz && (_a.baz = result.baz);
+var _b;
 (_b = b).baz || (_b.baz = result.baz);
+var _c;
 var _baz;
 (_baz = (_c = c).baz) !== null && _baz !== void 0 ? _baz : _c.baz = result.baz;
diff --git a/crates/swc/tests/tsc-references/logicalAssignment3(target=es2020).1.normal.js b/crates/swc/tests/tsc-references/logicalAssignment3(target=es2020).1.normal.js
@@ -1,5 +1,7 @@
 //// [logicalAssignment3.ts]
-var _a, _b, _c;
+var _a;
 (_a = a).baz && (_a.baz = result.baz);
+var _b;
 (_b = b).baz || (_b.baz = result.baz);
+var _c;
 (_c = c).baz ?? (_c.baz = result.baz);
diff --git a/crates/swc/tests/tsc-references/logicalAssignment9.1.normal.js b/crates/swc/tests/tsc-references/logicalAssignment9.1.normal.js
@@ -1,5 +1,6 @@
 //// [logicalAssignment9.ts]
-var _x, _x1;
+var _x;
 var _a;
 (_a = (_x = x).a) !== null && _a !== void 0 ? _a : _x.a = true;
+var _x1;
 (_x1 = x).a && (_x1.a = false);
diff --git a/crates/swc/tests/tsc-references/thisPrototypeMethodCompoundAssignmentJs.1.normal.js b/crates/swc/tests/tsc-references/thisPrototypeMethodCompoundAssignmentJs.1.normal.js
@@ -1,13 +1,14 @@
 //// [thisPrototypeMethodCompoundAssignmentJs.ts]
 //// [index.js]
-var _Element_prototype, /**
- * @this Node
- */ _Element_prototype1;
+var _Element_prototype;
 var _remove;
 (_remove = (_Element_prototype = Element.prototype).remove) !== null && _remove !== void 0 ? _remove : _Element_prototype.remove = function() {
     var _this_parentNode;
     (_this_parentNode = this.parentNode) === null || _this_parentNode === void 0 ? void 0 : _this_parentNode.removeChild(this);
 };
+var /**
+ * @this Node
+ */ _Element_prototype1;
 var _remove1;
 (_remove1 = (_Element_prototype1 = Element.prototype).remove) !== null && _remove1 !== void 0 ? _remove1 : _Element_prototype1.remove = function() {
     var _this_parentNode;
diff --git a/crates/swc_ecma_compat_es2021/Cargo.toml b/crates/swc_ecma_compat_es2021/Cargo.toml
@@ -19,6 +19,6 @@ unexpected_cfgs = { level = "warn", check-cfg = ['cfg(swc_ast_unknown)'] }
 tracing = { workspace = true }
 
 swc_ecma_ast             = { version = "19.0.0", path = "../swc_ecma_ast" }
-swc_ecma_compiler        = { version = "10.0.0", path = "../swc_ecma_compiler" }
+swc_ecma_transformer     = { version = "3.2.0", path = "../swc_ecma_transformer" }
 swc_ecma_transforms_base = { version = "32.0.0", path = "../swc_ecma_transforms_base" }
 swc_ecma_utils           = { version = "25.0.0", path = "../swc_ecma_utils" }
diff --git a/crates/swc_ecma_compat_es2021/src/logical_assignments.rs b/crates/swc_ecma_compat_es2021/src/logical_assignments.rs
@@ -1,9 +1,13 @@
 use swc_ecma_ast::Pass;
-use swc_ecma_compiler::{Compiler, Features};
 
+/// Creates a logical assignments transformation pass.
+///
+/// This enables both:
+/// - ES2021 logical assignment operators (&&=, ||=, ??=)
+/// - ES2020 nullish coalescing (to transform the ?? operator generated from
+///   ??=)
 pub fn logical_assignments() -> impl Pass {
-    Compiler::new(swc_ecma_compiler::Config {
-        includes: Features::LOGICAL_ASSIGNMENTS,
-        ..Default::default()
-    })
+    let mut options = swc_ecma_transformer::Options::default();
+    options.env.es2021.logical_assignment_operators = true;
+    options.into_pass()
 }
diff --git a/crates/swc_ecma_preset_env/src/lib.rs b/crates/swc_ecma_preset_env/src/lib.rs
@@ -158,8 +158,12 @@ where
     let pass = add_compiler!(
         pass,
         /* ES2022 */ | PrivatePropertyInObject
-        /* ES2021 */ | LogicalAssignmentOperators
     );
+
+    if !caniuse(Feature::LogicalAssignmentOperators) {
+        options.env.es2021.logical_assignment_operators = true;
+    }
+
     if !caniuse(Feature::ExportNamespaceFrom) {
         options.env.es2020.export_namespace_from = true;
     }
diff --git a/crates/swc_ecma_transformer/src/es2021/logical_assignment_operators.rs b/crates/swc_ecma_transformer/src/es2021/logical_assignment_operators.rs
diff --git a/crates/swc_ecma_transformer/src/es2021/mod.rs b/crates/swc_ecma_transformer/src/es2021/mod.rs
diff --git a/crates/swc_ecma_transforms_compat/tests/__swc_snapshots__/tests/es2021_logcal_assignments.rs/logical_member.js b/crates/swc_ecma_transforms_compat/tests/__swc_snapshots__/tests/es2021_logcal_assignments.rs/logical_member.js

Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,7 @@`
`1`	`1`	`"use strict";`
`2`	`2`	`function method() {`
`3`		`- var _obj;`
`4`	`3`	`const obj = {};`
	`4`	`+ var _obj;`
`5`	`5`	`(_obj = obj).prop ?? (_obj.prop = "x".repeat(10000000));`
`6`	`6`	`}`
`7`	`7`	`method(); // the large string should be eventually GCed along with the large string, but it will never happen in SWC+es2020`