需求:promise执行买菜做饭过程

需求:promise执行买菜做饭过程


1.买菜 
2.洗菜 
3.做饭 
4.吃饭 

 

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <meta name="viewport" content="width=device-width, initial-scale=1.0">
 6     <meta http-equiv="X-UA-Compatible" content="ie=edge">
 7     <title>Document</title>
 8 </head>
 9 <body>
10     <h2>需求:promise执行买菜做饭过程</h2>   <br>
11     1.买菜  <br>
12     2.洗菜  <br>
13     3.做饭  <br>
14     4.吃饭  <br>
15 </body>
16     <script>
17         let flag =1;
18         function step1(resolve,reject){
19            console.log("准备去买菜");
20            if(flag==1){
21              resolve("买好了")
22            }else{
23              reject("没菜了")
24            }
25         }
26         
27         function step2(resolve,reject){
28            console.log("洗菜");
29            if(flag==1){
30              resolve("洗好了");
31            }else{
32              reject("没水");
33            }
34         }
35         function step3(resolve,reject){
36            console.log("开始做饭");
37            if(flag==1){
38              resolve("做好了");
39            }else{
40              reject("煤气没了");
41            }
42         }
43         function step4(resolve,reject){
44            console.log("准备吃饭");
45            if(flag==1){
46              resolve("真好吃");
47            }else{
48              reject("真难吃");
49            }
50         }
51         function step5(resolve,reject){
52            console.log("剪刀石头布洗碗");
53            if(flag==0){
54              resolve("女朋友洗");
55            }else{
56              reject("不洗");
57            }
58         }
59         new Promise(step1).then((val1)=>{
60            console.log(val1);
61            return new Promise(step2)
62         }).then((val2)=>{
63            console.log(val2);
64            return new Promise(step3)
65         }).then((val3)=>{
66            console.log(val3)
67            return new Promise(step4)
68         }).then((val4)=>{
69            console.log(val4)
70            return new Promise(step5)
71         }).then((val5)=>{
72            console.log(val5)
73         })
74     </script>
75 </html>

 

posted @ 2019-01-04 16:44  你的张二狗  阅读(294)  评论(0)  编辑  收藏  举报