refactor: move prop decorator into core, expose initial props to initialziers

packages/runtime-core/__tests__/propDecorator.spec.ts

@@ -0,0 +1,65 @@
+import { prop } from '../src/optional/propDecorator'
+import { Component, createInstance } from '@vue/runtime-test'
+
+test('without options', () => {
+  let capturedThisValue
+  let capturedPropsValue
+
+  class Foo extends Component<{ p: number }> {
+    @prop
+    p: number
+
+    created() {
+      capturedThisValue = this.p
+      capturedPropsValue = this.$props.p
+    }
+  }
+
+  createInstance(Foo, {
+    p: 1
+  })
+  expect(capturedThisValue).toBe(1)
+  expect(capturedPropsValue).toBe(1)
+
+  // explicit override
+  createInstance(Foo, {
+    p: 2
+  })
+  expect(capturedThisValue).toBe(2)
+  expect(capturedPropsValue).toBe(2)
+})
+
+test('with options', () => {
+  let capturedThisValue
+  let capturedPropsValue
+  let capturedDataValue
+
+  class Foo extends Component<{ p: number }> {
+    @prop({
+      default: 1
+    })
+    p: number
+    // data property should be able to make use of prop
+    d: number = this.p + 1
+
+    created() {
+      capturedThisValue = this.p
+      capturedPropsValue = this.$props.p
+      capturedDataValue = this.d
+    }
+  }
+
+  // default value
+  createInstance(Foo)
+  expect(capturedThisValue).toBe(1)
+  expect(capturedPropsValue).toBe(1)
+  expect(capturedDataValue).toBe(2)
+
+  // explicit override
+  createInstance(Foo, {
+    p: 2
+  })
+  expect(capturedThisValue).toBe(2)
+  expect(capturedPropsValue).toBe(2)
+  expect(capturedDataValue).toBe(3)
+})