Merge pull request microsoft#40 from Microsoft/definiteAssignments

Use definite assignment assertions in class components.

Author: DanielRosenwasser

Diff for: README.md

@@ -443,9 +443,11 @@ import { Vue, Component, Prop } from "vue-property-decorator";
 
 @Component
 export default class HelloDecorator extends Vue {
-    @Prop() name: string;
-    @Prop() initialEnthusiasm: number;
+    @Prop() name!: string;
+    @Prop() initialEnthusiasm!: number;
+
     enthusiasm = this.initialEnthusiasm;
+
     increment() {
         this.enthusiasm++;
     }
@@ -454,6 +456,7 @@ export default class HelloDecorator extends Vue {
             this.enthusiasm--;
         }
     }
+
     get exclamationMarks(): string {
         return Array(this.enthusiasm + 1).join('!');
     }
@@ -463,6 +466,8 @@ export default class HelloDecorator extends Vue {
 Instead of using `Vue.extend` to define our component, we create a class extending `Vue` and decorate it using the `@Component` decorator from the `vue-class-component` package (which was re-exported from the `vue-property-decorator` package).
 
 Properties are defined by prefixing instance variables with the `@Prop()` decorator from the `vue-property-decorator` package.
+Because the `--strictPropertyInitialization` option is on, we need to tell TypeScript that Vue will initialize our properties by appending a `!` to them.
+This tells TypeScript "hey, relax, someone else is going to assign this property a value."
 
 Regular instance variables, such as `enthusiasm` in our example, are automatically made available for data binding to the template, just as if they had been defined in the `data` field.
 Note that all variables must be set to a value other than `undefined` for the binding to work.

Diff for: package.json

@@ -23,7 +23,7 @@
   "devDependencies": {
     "css-loader": "^0.28.1",
     "ts-loader": "^2.0.3",
-    "typescript": "^2.3.2",
+    "typescript": "^2.7.2",
     "vue-loader": "^12.0.3",
     "vue-template-compiler": "^2.5.2",
     "webpack": "^2.5.0"

Diff for: src/components/HelloDecorator.vue

@@ -13,8 +13,8 @@ import { Vue, Component, Prop } from "vue-property-decorator";
 
 @Component
 export default class HelloDecorator extends Vue {
-    @Prop() name: string;
-    @Prop() initialEnthusiasm: number;
+    @Prop() name!: string;
+    @Prop() initialEnthusiasm!: number;
 
     enthusiasm = this.initialEnthusiasm;
 

Diff for: yarn.lock

@@ -2040,6 +2040,10 @@ reduce-function-call@^1.0.1:
   dependencies:
     balanced-match "^0.4.2"
 
+reflect-metadata@^0.1.10:
+  version "0.1.12"
+  resolved "https://registry.yarnpkg.com/reflect-metadata/-/reflect-metadata-0.1.12.tgz#311bf0c6b63cd782f228a81abe146a2bfa9c56f2"
+
 regenerate@^1.2.1:
   version "1.3.2"
   resolved "https://registry.yarnpkg.com/regenerate/-/regenerate-1.3.2.tgz#d1941c67bad437e1be76433add5b385f95b19260"
@@ -2382,9 +2386,9 @@ tweetnacl@^0.14.3, tweetnacl@~0.14.0:
   version "0.14.5"
   resolved "https://registry.yarnpkg.com/tweetnacl/-/tweetnacl-0.14.5.tgz#5ae68177f192d4456269d108afa93ff8743f4f64"
 
-typescript@^2.3.2:
-  version "2.3.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.3.2.tgz#f0f045e196f69a72f06b25fd3bd39d01c3ce9984"
+typescript@^2.7.2:
+  version "2.7.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.7.2.tgz#2d615a1ef4aee4f574425cdff7026edf81919836"
 
 uglify-js@^2.8.5:
   version "2.8.22"
@@ -2461,6 +2465,10 @@ [email protected]:
   dependencies:
     indexof "0.0.1"
 
+vue-class-component@^6.0.0:
+  version "6.2.0"
+  resolved "https://registry.yarnpkg.com/vue-class-component/-/vue-class-component-6.2.0.tgz#7adb1daa9a868c75f30f97f33f4f1b94aee62089"
+
 vue-hot-reload-api@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/vue-hot-reload-api/-/vue-hot-reload-api-2.1.0.tgz#9ca58a6e0df9078554ce1708688b6578754d86de"
@@ -2483,9 +2491,16 @@ vue-loader@^12.0.3:
     vue-style-loader "^3.0.0"
     vue-template-es2015-compiler "^1.2.2"
 
-"vue-router@https://github.com/DanielRosenwasser/vue-router#01b8593cf69c2a5077df45e37e2b24d95bf35ce3":
-  version "2.3.0"
-  resolved "https://github.com/DanielRosenwasser/vue-router#01b8593cf69c2a5077df45e37e2b24d95bf35ce3"
+vue-property-decorator@^6.0.0:
+  version "6.0.0"
+  resolved "https://registry.yarnpkg.com/vue-property-decorator/-/vue-property-decorator-6.0.0.tgz#bb651b293542e31db0d24f36f4b0250ef08d8515"
+  dependencies:
+    reflect-metadata "^0.1.10"
+    vue-class-component "^6.0.0"
+
+vue-router@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/vue-router/-/vue-router-3.0.1.tgz#d9b05ad9c7420ba0f626d6500d693e60092cc1e9"
 
 vue-style-loader@^3.0.0:
   version "3.0.1"
@@ -2494,9 +2509,9 @@ vue-style-loader@^3.0.0:
     hash-sum "^1.0.2"
     loader-utils "^1.0.2"
 
-vue-template-compiler@2.2.1:
-  version "2.2.1"
-  resolved "https://registry.yarnpkg.com/vue-template-compiler/-/vue-template-compiler-2.2.1.tgz#ca5e43db50dc6e761e3c1296313de33091783511"
+vue-template-compiler@^2.5.2:
+  version "2.5.16"
+  resolved "https://registry.yarnpkg.com/vue-template-compiler/-/vue-template-compiler-2.5.16.tgz#93b48570e56c720cdf3f051cc15287c26fbd04cb"
   dependencies:
     de-indent "^1.0.2"
     he "^1.1.0"
@@ -2505,9 +2520,9 @@ vue-template-es2015-compiler@^1.2.2:
   version "1.5.2"
   resolved "https://registry.yarnpkg.com/vue-template-es2015-compiler/-/vue-template-es2015-compiler-1.5.2.tgz#a0a6c50c941d2a4abda963f2f42c337ac450ee95"
 
-"vue@https://github.com/DanielRosenwasser/vue#540a38fb21adb7a7bc394c65e23e6cffb36cd867":
-  version "2.2.1"
-  resolved "https://github.com/DanielRosenwasser/vue#540a38fb21adb7a7bc394c65e23e6cffb36cd867"
+vue@^2.5.2:
+  version "2.5.16"
+  resolved "https://registry.yarnpkg.com/vue/-/vue-2.5.16.tgz#07edb75e8412aaeed871ebafa99f4672584a0085"
 
 watchpack@^1.3.1:
   version "1.3.1"