From c71ee1de88022ad0f0794533dad7e614e9ea0c14 Mon Sep 17 00:00:00 2001
From: makepost <makepost@firemail.cc>
Date: Fri, 23 Mar 2018 18:58:32 +0200
Subject: [PATCH] Decorate: Fix in type-checked JS, resolves #1448

---
 src/api/decorate.ts   |  4 ++--
 src/api/observable.ts |  2 +-
 test/base/decorate.js | 43 ++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/src/api/decorate.ts b/src/api/decorate.ts
index c5ccca5aa..9c3b42fc8 100644
--- a/src/api/decorate.ts
+++ b/src/api/decorate.ts
@@ -2,11 +2,11 @@ import { invariant, isPlainObject } from "../utils/utils"
 
 export function decorate<T>(
     clazz: new (...args: any[]) => T,
-    decorators: { [P in keyof T]: MethodDecorator | PropertyDecorator }
+    decorators: { [P in keyof T]?: MethodDecorator | PropertyDecorator }
 ): void
 export function decorate<T>(
     object: T,
-    decorators: { [P in keyof T]: MethodDecorator | PropertyDecorator }
+    decorators: { [P in keyof T]?: MethodDecorator | PropertyDecorator }
 ): T
 export function decorate(thing: any, decorators: any) {
     process.env.NODE_ENV !== "production" &&
diff --git a/src/api/observable.ts b/src/api/observable.ts
index d8bf38ead..83610cbdf 100644
--- a/src/api/observable.ts
+++ b/src/api/observable.ts
@@ -92,7 +92,7 @@ function createObservable(v: any, arg2?: any, arg3?: any) {
 export interface IObservableFactory {
     // observable overloads
     (value: number | string | null | undefined | boolean): never // Nope, not supported, use box
-    (target: Object, key: string, baseDescriptor?: PropertyDescriptor): any // decorator
+    (target: Object, key: string | symbol, baseDescriptor?: PropertyDescriptor): any // decorator
     <T = any>(value: T[], options?: CreateObservableOptions): IObservableArray<T>
     <K = any, V = any>(value: Map<K, V>, options?: CreateObservableOptions): ObservableMap<K, V>
     <T extends Object>(
diff --git a/test/base/decorate.js b/test/base/decorate.js
index da9df1c3d..f620c55f0 100644
--- a/test/base/decorate.js
+++ b/test/base/decorate.js
@@ -1,3 +1,5 @@
+// @ts-check
+
 import {
     observable,
     computed,
@@ -17,6 +19,7 @@ import {
 
 test("decorate should work", function() {
     class Box {
+        // @ts-ignore
         uninitialized
         height = 20
         sizes = [2]
@@ -33,7 +36,9 @@ test("decorate should work", function() {
             )
         }
         addSize() {
+            // @ts-ignore
             this.sizes.push([3])
+            // @ts-ignore
             this.sizes.push([4])
         }
         constructor() {
@@ -105,7 +110,9 @@ test("decorate should work with plain object", function() {
             )
         },
         addSize() {
+            // @ts-ignore
             this.sizes.push([3])
+            // @ts-ignore
             this.sizes.push([4])
         }
     }
@@ -171,7 +178,9 @@ test("decorate should work with Object.create", function() {
             )
         },
         addSize() {
+            // @ts-ignore
             this.sizes.push([3])
+            // @ts-ignore
             this.sizes.push([4])
         }
     }
@@ -233,12 +242,16 @@ test("decorate should work with constructor function", function() {
             configurable: true,
             enumerable: false,
             get() {
+                /** @type {Box} */
+                var t /** @type {any} */ = this
+
                 return (
-                    this.undeclared *
-                    this.height *
-                    this.sizes.length *
-                    this.someFunc() *
-                    (this.uninitialized ? 2 : 1)
+                    // @ts-ignore
+                    t.undeclared *
+                    t.height *
+                    t.sizes.length *
+                    t.someFunc() *
+                    (t.uninitialized ? 2 : 1)
                 )
             }
         })
@@ -262,6 +275,7 @@ test("decorate should work with constructor function", function() {
     }
 
     const box = new Box()
+    // @ts-ignore
     box.undeclared = 1
 
     expect(isObservableObject(box)).toBe(true)
@@ -278,6 +292,7 @@ test("decorate should work with constructor function", function() {
     var ar = []
 
     autorun(() => {
+        // @ts-ignore
         ar.push(box.width)
     })
 
@@ -292,11 +307,14 @@ test("decorate should work with constructor function", function() {
     expect(ar.slice()).toEqual([40, 20, 60, 210, 420])
     box.addSize()
     expect(ar.slice()).toEqual([40, 20, 60, 210, 420, 700])
+    // @ts-ignore
     box.undeclared = 2
     expect(ar.slice()).toEqual([40, 20, 60, 210, 420, 700, 1400])
 
     const box2 = new Box()
+    // @ts-ignore
     box2.undeclared = 1
+    // @ts-ignore
     expect(box2.width).toBe(40) // no shared state!
 })
 
@@ -318,3 +336,18 @@ test("decorate should work with inheritance through Object.create", () => {
     expect(child2.x).toBe(5)
     expect(child1.x).toBe(4)
 })
+
+test("decorate should work with ES6 constructor", () => {
+    class Todo {
+        constructor() {
+            this.finished = false
+            this.id = Math.random()
+            this.title = ""
+        }
+    }
+
+    decorate(Todo, {
+        finished: observable,
+        title: observable
+    })
+})