Reuse computed key memoiser (#16159)

babel · Dec 11, 2023 · 93dd407 · 93dd407
1 parent 4c78c0d
commit 93dd407
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Showing 2 changed files with 33 additions and 18 deletions.
diff --git a/packages/babel-helper-create-class-features-plugin/src/misc.ts b/packages/babel-helper-create-class-features-plugin/src/misc.ts
@@ -142,21 +142,37 @@ export function extractComputedKeys(
     // Make sure computed property names are only evaluated once (upon class definition)
     // and in the right order in combination with static properties
     if (!computedKey.isConstantExpression()) {
-      const ident = path.scope.generateUidIdentifierBasedOnNode(
-        computedNode.key,
-      );
-      // Declaring in the same block scope
-      // Ref: https://github.com/babel/babel/pull/10029/files#diff-fbbdd83e7a9c998721c1484529c2ce92
-      path.scope.push({
-        id: ident,
-        kind: "let",
-      });
-      declarations.push(
-        t.expressionStatement(
-          t.assignmentExpression("=", t.cloneNode(ident), computedNode.key),
-        ),
-      );
-      computedNode.key = t.cloneNode(ident);
+      const scope = path.scope;
+      const isUidReference =
+        t.isIdentifier(computedKey.node) && scope.hasUid(computedKey.node.name);
+      const isMemoiseAssignment =
+        computedKey.isAssignmentExpression({ operator: "=" }) &&
+        t.isIdentifier(computedKey.node.left) &&
+        scope.hasUid(computedKey.node.left.name);
+      if (isUidReference) {
+        continue;
+      } else if (isMemoiseAssignment) {
+        declarations.push(t.expressionStatement(t.cloneNode(computedNode.key)));
+        computedNode.key = t.cloneNode(
+          (computedNode.key as t.AssignmentExpression).left as t.Identifier,
+        );
+      } else {
+        const ident = path.scope.generateUidIdentifierBasedOnNode(
+          computedNode.key,
+        );
+        // Declaring in the same block scope
+        // Ref: https://github.com/babel/babel/pull/10029/files#diff-fbbdd83e7a9c998721c1484529c2ce92
+        scope.push({
+          id: ident,
+          kind: "let",
+        });
+        declarations.push(
+          t.expressionStatement(
+            t.assignmentExpression("=", t.cloneNode(ident), computedNode.key),
+          ),
+        );
+        computedNode.key = t.cloneNode(ident);
+      }
     }
   }
 

diff --git a/...-plugin-transform-class-properties/test/fixtures/nested-class/super-call-in-key/output.js b/...-plugin-transform-class-properties/test/fixtures/nested-class/super-call-in-key/output.js
@@ -12,13 +12,12 @@ let Outer = /*#__PURE__*/function (_Hello) {
   babelHelpers.inherits(Outer, _Hello);
   var _super = babelHelpers.createSuper(Outer);
   function Outer() {
-    let _this2;
     var _this;
     babelHelpers.classCallCheck(this, Outer);
-    _this2 = _this = _super.call(this);
+    _this = _super.call(this);
     let Inner = /*#__PURE__*/babelHelpers.createClass(function Inner() {
       babelHelpers.classCallCheck(this, Inner);
-      babelHelpers.defineProperty(this, _this2, "hello");
+      babelHelpers.defineProperty(this, _this, "hello");
     });
     return babelHelpers.possibleConstructorReturn(_this, new Inner());
   }