Fix 'Missing class properties transform' error when parsing class properties with Typescript syntax (#8007)

packages/babel-plugin-proposal-class-properties/test/fixtures/compile-to-class/constructor-collision-ignores-types-loose/output.js

@@ -1,7 +1,6 @@
 class C {
   // Output should not use `_initialiseProps`
   constructor(T) {
-    this.x = void 0;
     this.y = 0;
   }
 

packages/babel-plugin-proposal-class-properties/test/fixtures/compile-to-class/constructor-collision-ignores-types/output.js

@@ -3,8 +3,6 @@ function _defineProperty(obj, key, value) { if (key in obj) { Object.definePrope
 class C {
   // Output should not use `_initialiseProps`
   constructor(T) {
-    _defineProperty(this, "x", void 0);
-
     _defineProperty(this, "y", 0);
   }
 

packages/babel-plugin-transform-typescript/src/index.js

@@ -183,10 +183,22 @@ export default declare((api, { jsxPragma = "React" }) => {
         if (node.abstract) node.abstract = null;
       },
 
-      Class({ node }) {
+      Class(path) {
+        const { node } = path;
+
         if (node.typeParameters) node.typeParameters = null;
         if (node.superTypeParameters) node.superTypeParameters = null;
         if (node.implements) node.implements = null;
+
+        // Same logic is used in babel-plugin-transform-flow-strip-types:
+        // We do this here instead of in a `ClassProperty` visitor because the class transform
+        // would transform the class before we reached the class property.
+        path.get("body.body").forEach(child => {
+          if (child.isClassProperty()) {
+            child.node.typeAnnotation = null;
+            if (!child.node.value) child.remove();
+          }
+        });
       },
 
       Function({ node }) {