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@@ -0,0 +1,125 @@
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+/**
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+ * js是单线程语言，弱类型类型
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+ */
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+/**同步
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+ * 代码自上而下一行一行的执行 且执行完才会去执行下一行代码
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+*/
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+var a = 10;
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+console.log(a,'a');
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+var b = 20;
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+console.log(b,'b');
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+/**异步:setTimeOut setInterval、Promise、事件 */
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+// setInterval(()=>{
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+// console.log("这个事件");
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+// },1000)
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+/**回调函数：同步或者异步
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+ * 定义：一个函数（A）作为实参传给另一个函数(B)，并在B中被调用，则为回调函数
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+ */
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+const test1 = () => {
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+ document.write("hello")
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+}
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+setTimeout(test1,1000);
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+/**回调地狱 */
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+// setTimeout(()=>{
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+// console.log(2);
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+// setTimeout(()=>{
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+// console.log(1);
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+// setTimeout(()=>{
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+// console.log(3);
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+// },1000)
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+// },1000)
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+// },1000)
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+
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+/**
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+ * Promise 异步编程
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+ * 将异步的操作 用同步的流程表达出来
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+ * 三种状态： pending 进行中
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+ * reject 已失败
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+ * resolve/fulfilled 已成功
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+ *
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+ */
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+/**第一种 */
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+// new Promise((resolve,reject) => {
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+// // resolve 成功时调用
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+// // reject 失败时调用
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+// setTimeout(()=>{
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+// console.log(4);
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+// // 只会调用第一个方法 后续则不生效
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+// resolve();
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+// reject();
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+// },1000)
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+// }).then(()=> {
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+// console.log("成功")
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+// }).catch(()=>{
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+// console.log("失败")
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+// })
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+/**第二种 */
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+// let back = new Promise((resolve,reject)=>{
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+// setTimeout(()=>{
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+// console.log(5)
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+// resolve();
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+// },1000)
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+// })
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+// back.then(()=>{
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+// console.log("111")
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+// })
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+// back.catch(()=>{
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+// console.log("222")
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+// })
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+var newPromise = new Promise((resolve,reject)=>{reject()})
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+newPromise.then(()=>{
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+ console.log(newPromise,"输出")
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+})
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+newPromise.catch(()=>{
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+ console.log(newPromise,"catch")
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+})
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+
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+// new Promise((resolve,reject) => {
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+// setTimeout(()=>{
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+// console.log(1);
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+// resolve();
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+// },1000)
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+// }).then(()=>{
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+// new Promise(()=>{
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+
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+// })
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+// }).catch(()=>{
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+
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+// })
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+
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+let p1 = new Promise((resolve,reject)=>{
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+ setTimeout(()=>{
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+ console.log(1);
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+ reject();
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+ },1000)
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+})
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+let p2 = new Promise((resolve,reject)=>{
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+ setTimeout(()=>{
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+ console.log(2);
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+ reject();
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+ },1200)
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+})
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+let p3 = new Promise((resolve,reject)=>{
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+ setTimeout(()=>{
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+ console.log(3);
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+ resolve();
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+ },800)
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+})
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+/**
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+ * Promise.all判断多个promise
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+ * 当传入的都成功 则成功
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+ */
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+// Promise.all([p1,p2,p3]).then(()=>{
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+// console.log("成功了");
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+// }).catch(()=>{
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+// console.log("失败了");
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+// })
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+/**
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+ * Promise.race 第一个执行的成功则成功
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+ */
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+Promise.race([p1,p2,p3]).then(()=>{
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+ console.log("成功了");
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+}).catch(()=>{
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+ console.log("失败了");
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+})
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+
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e