feat(exercise3): 完成 Exercise3 - 手写简易 Promise

.github/workflows/homework8.yml

@@ -0,0 +1,29 @@
+# This workflow will do a clean installation of node dependencies, cache/restore them, build the source code and run tests across different versions of node
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
+
+name: Node.js CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [16.x]
+        # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v3
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: yarn
+    - run: yarn test

index.js

@@ -1,3 +1,9 @@
+const PROMISE_STATUS_ENUM = {
+  PENDING: "pending",
+  FULFILLED: "fulfilled",
+  REJECTED: "rejected"
+}
+
 function myPromise(constructor) {
   let self = this;
 
@@ -8,15 +14,20 @@ function myPromise(constructor) {
   self.reason = undefined;//定义状态为rejected的时候的状态
 
   function resolve(value) {
-
     // TODO resolve如何改变状态及返回结果
-
+    if(self.status === PROMISE_STATUS_ENUM.PENDING) {
+      self.status = PROMISE_STATUS_ENUM.FULFILLED
+      self.value = value
+    }
   }
 
   function reject(reason) {
 
     // TODO reject如何改变状态及返回结果
-
+    if(self.status === PROMISE_STATUS_ENUM.PENDING) {
+      self.status = PROMISE_STATUS_ENUM.REJECTED
+      self.reason = reason
+    }
   }
 
   //捕获构造异常
@@ -36,6 +47,11 @@ function myPromise(constructor) {
 myPromise.prototype.then = function (onFullfilled, onRejected) {
 
   //TODO then如何实现
+  if(this.status === PROMISE_STATUS_ENUM.FULFILLED) {
+    onFullfilled(this.value)
+  } else if (this.status === PROMISE_STATUS_ENUM.REJECTED) {
+    onRejected(this.reason)
+  }
 
 }
 module.exports = myPromise