fix unshiftContainer and insertBefore

packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/exec.js

@@ -0,0 +1,23 @@
+const classes = [];
+for (let i = 0; i <= 10; ++i) {
+  classes.push(
+    class A {
+      [i] = `computed field ${i}`;
+      static foo = `static field ${i}`;
+      #bar = `private field ${i}`;
+      getBar() {
+        return this.#bar;
+      }
+    }
+  );
+}
+
+// for(let i=0; i<= 10; ++i) {
+//   const clazz = classes[i];
+//   expect(clazz.foo).toBe('static field ' + i);
+
+//   const instance = new clazz();
+//   expect(Object.getOwnPropertyNames(instance)).toEqual([String(i)])
+//   expect(instance[i]).toBe('computed field ' + i);
+//   expect(instance.getBar()).toBe('private field ' + i);
+// }

packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/input.js

@@ -0,0 +1,13 @@
+const classes = [];
+for (let i = 0; i <= 10; ++i) {
+  classes.push(
+    class A {
+      [i] = `computed field ${i}`;
+      static foo = `static field ${i}`;
+      #bar = `private field ${i}`;
+      getBar() {
+        return this.#bar;
+      }
+    }
+  );
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["external-helpers", "proposal-class-properties"]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/regression/8882/output.js

@@ -0,0 +1,21 @@
+const classes = [];
+
+for (let i = 0; i <= 10; ++i) {
+  var _class, _i, _temp, _bar;
+
+  classes.push((_temp = (_i = i, _class = class A {
+    constructor() {
+      babelHelpers.defineProperty(this, _i, `computed field ${i}`);
+
+      _bar.set(this, {
+        writable: true,
+        value: `private field ${i}`
+      });
+    }
+
+    getBar() {
+      return babelHelpers.classPrivateFieldGet(this, _bar);
+    }
+
+  }), _bar = new WeakMap(), babelHelpers.defineProperty(_class, "foo", `static field ${i}`), _temp));
+}

packages/babel-traverse/src/path/modification.js

@@ -221,7 +221,7 @@ export function unshiftContainer(listKey, nodes) {
     key: 0,
   });
 
-  return path.insertBefore(nodes);
+  return path._containerInsertBefore(nodes);
 }
 
 export function pushContainer(listKey, nodes) {

packages/babel-traverse/test/modification.js

@@ -36,6 +36,19 @@ describe("modification", function() {
 
       expect(generateCode(rootPath)).toBe("function test(a) {\n  b;\n}");
     });
+
+    it("properly handles more than one arguments", function() {
+      const code = "foo(a, b);";
+      const ast = parse(code);
+      traverse(ast, {
+        CallExpression: function(path) {
+          path.pushContainer("arguments", t.identifier("d"));
+          expect(generateCode(path)).toBe("foo(a, b, d);");
+          path.pushContainer("arguments", t.stringLiteral("s"));
+          expect(generateCode(path)).toBe(`foo(a, b, d, "s");`);
+        },
+      });
+    });
   });
   describe("unshiftContainer", function() {
     it("unshifts identifier into params", function() {