Merge pull request #64 from inversify/issue-674

Implemented inversify/InversifyJS/issues/674

Author: remojansen

README.md

@@ -79,6 +79,35 @@ class Shuriken implements ThrowableWeapon {
 
 ```
 
+### Using @provide multiple times
+
+If you try to apply `@provide` multiple times:
+
+```ts
+@provide("Ninja")
+@provide("SilentNinja")
+class Ninja {
+    // ...
+}
+```
+
+The library will throw an exception:
+
+> Cannot apply @injectable decorator multiple times. Please use @provide(ID, true) if you are trying to declare multiple bindings!
+
+We throw an exception to ensure that you are are not trying to apply `@provide` multiple times by mistake.
+
+You can overcome this by passing the `force` argument to `@provide`:
+
+```ts
+@provide("Ninja", true)
+@provide("SilentNinja", true)
+class Ninja {
+    // ...
+}
+```
+
+
 ### Using classes, string literals & symbols as identifiers
 When you invoke `@provide` using classes:
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "inversify-binding-decorators",
-  "version": "3.0.1",
+  "version": "3.1.0",
   "description": "An utility that allows developers to declare InversifyJS bindings using ES2016 decorators",
   "main": "lib/index.js",
   "jsnext:main": "es/index.js",

src/decorator/provide.ts

@@ -1,16 +1,34 @@
-import { decorate, injectable } from "inversify";
+import { decorate, injectable, METADATA_KEY } from "inversify";
 import { interfaces } from "inversify";
 
 function provide(container: interfaces.Container) {
-
-  // function is named for testing
-  return function _provide(serviceIdentifier: interfaces.ServiceIdentifier<any>) {
+  return function _provide(
+    serviceIdentifier: interfaces.ServiceIdentifier<any>,
+    force?: boolean
+  ) {
     let bindingWhenOnSyntax = container.bind<any>(serviceIdentifier).to(<any>null);
     return function (target: any) {
-      decorate(injectable(), target);
-      let binding: interfaces.Binding<any> = (<any>bindingWhenOnSyntax)._binding;
-      binding.implementationType = target;
-      return target;
+
+      const isAlreadyDecorated = Reflect.hasOwnMetadata(METADATA_KEY.PARAM_TYPES, target);
+      const redecorateWithInject = force === true;
+
+     if (redecorateWithInject === true && isAlreadyDecorated === false) {
+        decorate(injectable(), target);
+      } else if (redecorateWithInject === true && isAlreadyDecorated === true) {
+        // Do nothing
+      } else {
+        try {
+          decorate(injectable(), target);
+        } catch (e) {
+          throw new Error(`${e.message} ` +
+          "Please use @provide(ID, true) if you are trying to declare multiple bindings!");
+        }
+     }
+
+     let binding: interfaces.Binding<any> = (<any>bindingWhenOnSyntax)._binding;
+     binding.implementationType = target;
+     return target;
+
     };
   };
 }

test/decorator/provide.test.ts

@@ -29,4 +29,38 @@ describe("provide", () => {
 
     });
 
+    it("Should throw if applied more than once without force flag", () => {
+
+        const myContainer = new Container();
+        const provide = _provide(myContainer);
+
+        function shouldThrow() {
+            @provide("Ninja")
+            @provide("SilentNinja")
+            class Ninja {}
+            return Ninja;
+        }
+
+        expect(shouldThrow).to.throw(
+            "Cannot apply @injectable decorator multiple times. " +
+            "Please use @provide(ID, true) if you are trying to declare multiple bindings!");
+
+    });
+
+    it("Should work if applied more than once with force flag", () => {
+
+        const myContainer = new Container();
+        const provide = _provide(myContainer);
+
+        function shouldThrow() {
+            @provide("Ninja", true)
+            @provide("SilentWarrior", true)
+            class Ninja {}
+            return Ninja;
+        }
+
+        expect(shouldThrow).not.to.throw();
+
+    });
+
 });

tslint.json

@@ -34,7 +34,6 @@
     "no-switch-case-fall-through": false,
     "no-trailing-whitespace": true,
     "no-unused-expression": true,
-    "no-use-before-declare": true,
     "no-var-keyword": true,
     "object-literal-sort-keys": true,
     "one-line": [true,