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.github/workflows/node1.js.yml

@@ -0,0 +1,31 @@
+# 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: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [12.x, 14.x, 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 }}
+        cache: 'npm'
+    - run: npm ci
+    - run: npm run build --if-present
+    - run: npm test

index.js

@@ -1,41 +1,86 @@
-function myPromise(constructor) {
+function myPromise(executor) {
+  // 定义promise的状态
   let self = this;
+  self.status = "pendding";
+  self.value = null; // 成功之后 返回数据
+  self.reason = null;  // 失败之后返回原因
 
-  self.status = "pending" //定义状态改变前的初始状态
-
-  self.value = undefined;//定义状态为resolved的时候的状态
-
-  self.reason = undefined;//定义状态为rejected的时候的状态
+  // 这个是 发布订阅
+  self.fulfilledCallbackList = [];
+  self.rejectCallbackList = [];
 
+  // 定义完成时的方法
   function resolve(value) {
-
-    // TODO resolve如何改变状态及返回结果
-
+      if (self.status == "pendding") {
+          self.status = "fulfilled";
+          self.value = value;
+          self.fulfilledCallbackList.forEach(item => item(value));
+      }
   }
-
-  function reject(reason) {
-
-    // TODO reject如何改变状态及返回结果
-
+  // 这个是 异常时候的方法
+  function reject(err) {
+      if (self.status == "pendding") {
+          self.status = "rejected";
+          self.reason = err;
+          self.rejectCallbackList.forEach(item => item(err));
+      }
   }
 
-  //捕获构造异常
-
+  // 立即执行 executor里面的方法
   try {
+     executor(resolve, reject);
+  } catch (err) {
+      reject(err.message);
+  }
+}
 
-    constructor(resolve, reject);
+// 这个是 原型链上面的 then 方法
+myPromise.prototype.then = function (onFulfilled, onRejected) {
+  // 这里 还要 判断一下 传入进来 是不是一个方法
+  onFulfilled = typeof onFulfilled == 'function' ? onFulfilled : function (data) { resolve(data) };
+  onRejected = typeof onRejected == 'function' ? onRejected : function (err) { throw err; }
 
-  } catch (e) {
+  let self = this;
 
-    reject(e);
+  // 这里是 then 里面的回调部分
+  if (self.status == "fulfilled") {
+      // 链式调用 就是 直接返回一个 Promise
+      return new myPromise((resolve, reject) => {
+          try {
+              let x = onFulfilled(self.value);
+              x instanceof myPromise ? x.then(resolve, reject) : resolve(x);
+          } catch (err) {
+              reject(err);
+          }
+
+      });
+  }
 
+  // 这个是 失败的状态
+  if (self.status == "rejected") {
+      return new myPromise((resolve, reject) => {
+          try {
+              let x = onRejected(self.reason);
+              x instanceof myPromise ? x.then(resolve, reject) : resolve(x);
+          } catch (err) {
+              reject(err);
+          }
+      });
   }
 
+  // 这个是 pendding的状态
+  if (self.status == "pendding") {
+      return new myPromise((resolve, reject) => {
+          self.fulfilledCallbackList.push(() => {
+              let x = onFulfilled(self.value);
+              x instanceof myPromise ? x.then(resolve, reject) : resolve(x);
+          });
+          self.rejectCallbackList.push(() => {
+              let x = onRejected(self.reason);
+              x instanceof myPromise ? x.then(resolve, reject) : resolve(x);
+          });
+      });
+  }
 }
 
-myPromise.prototype.then = function (onFullfilled, onRejected) {
-
-  //TODO then如何实现
-
-}
 module.exports = myPromise