From 4d125c391a9633ecdcaa0a6c0453170a611e869d Mon Sep 17 00:00:00 2001
From: Pierre-Marie Dartus <dartus.pierremarie@gmail.com>
Date: Wed, 4 Jul 2018 04:44:33 -0700
Subject: [PATCH] Typescript: Avoid stripping class properties when a decorator
 is set (#8238)

The `babel-plugin-transform-typescript` removes class properties without value regardless if decorators are assigned to it or not.
---
 packages/babel-plugin-transform-typescript/src/index.js  | 9 ++++-----
 .../test/fixtures/class/properties/input.js              | 2 ++
 .../test/fixtures/class/properties/options.json          | 6 ++++++
 .../test/fixtures/class/properties/output.js             | 4 ++++
 4 files changed, 16 insertions(+), 5 deletions(-)
 create mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/class/properties/options.json

diff --git a/packages/babel-plugin-transform-typescript/src/index.js b/packages/babel-plugin-transform-typescript/src/index.js
index 9ba2e23d89..f7f2b304f6 100644
--- a/packages/babel-plugin-transform-typescript/src/index.js
+++ b/packages/babel-plugin-transform-typescript/src/index.js
@@ -157,10 +157,6 @@ export default declare((api, { jsxPragma = "React" }) => {
 
       ClassProperty(path) {
         const { node } = path;
-        if (!node.value) {
-          path.remove();
-          return;
-        }
 
         if (node.accessibility) node.accessibility = null;
         if (node.abstract) node.abstract = null;
@@ -196,7 +192,10 @@ export default declare((api, { jsxPragma = "React" }) => {
         path.get("body.body").forEach(child => {
           if (child.isClassProperty()) {
             child.node.typeAnnotation = null;
-            if (!child.node.value) child.remove();
+
+            if (!child.node.value && !child.node.decorators) {
+              child.remove();
+            }
           }
         });
       },
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/input.js b/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/input.js
index ce12b25f6f..abb53ac69b 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/input.js
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/input.js
@@ -2,4 +2,6 @@ class C {
     public a?: number;
     private b: number = 0;
     readonly c!: number = 1;
+    @foo d: number;
+    @foo e: number = 3;
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/options.json b/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/options.json
new file mode 100644
index 0000000000..43bd3d3759
--- /dev/null
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/options.json
@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    "transform-typescript",
+    ["syntax-decorators", { "legacy": true }]
+  ]
+}
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/output.js b/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/output.js
index 77e91a62b0..8dd079732d 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/output.js
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/class/properties/output.js
@@ -1,4 +1,8 @@
 class C {
   b = 0;
   c = 1;
+  @foo
+  d;
+  @foo
+  e = 3;
 }