|
| 1 | +//call back |
| 2 | +// function sum (a,b,sum){ |
| 3 | +// return console.log(a+b) |
| 4 | +// } |
| 5 | +// function para(a,b,sum){ |
| 6 | +// sum(a,b) |
| 7 | +// } |
| 8 | +// para(1,2,sum) |
| 9 | + |
| 10 | +// function minus (a,b){ |
| 11 | +// return console.log(a-b) |
| 12 | +// } |
| 13 | +// function cal(a,b,minus){ |
| 14 | +// minus(a,b) |
| 15 | +// } |
| 16 | +// cal(5,1,minus) |
| 17 | + |
1 | 18 | //callback hell |
2 | 19 |
|
3 | | -function database(id,database){ |
4 | | - setTimeout(()=>{ |
5 | | - console.log("data of",id) |
6 | | - if(database){ |
7 | | - database() |
8 | | - } |
9 | | - },2000) |
| 20 | +// function database(id,database){ |
| 21 | +// setTimeout(()=>{ |
| 22 | +// console.log("data of",id) |
| 23 | +// if(database){ |
| 24 | +// database() |
| 25 | +// } |
| 26 | +// },2000) |
10 | 27 |
|
11 | 28 |
|
12 | 29 |
|
13 | | -} |
14 | | -console.log("getting next data 3004") |
15 | | -database(3004,()=>{ |
16 | | - console.log("getting next data 3005") |
17 | | - database(3005,()=>{ |
18 | | - console.log("getting next data 3006") |
19 | | - database(3006,()=>{ |
20 | | - console.log("getting next data 3007") |
21 | | - database(3007) |
22 | | - }) |
| 30 | +// } |
| 31 | +// console.log("getting next data 3004") |
| 32 | +// database(3004,()=>{ |
| 33 | +// console.log("getting next data 3005") |
| 34 | +// database(3005,()=>{ |
| 35 | +// console.log("getting next data 3006") |
| 36 | +// database(3006,()=>{ |
| 37 | +// console.log("getting next data 3007") |
| 38 | +// database(3007) |
| 39 | +// }) |
| 40 | +// }) |
| 41 | +// }) |
| 42 | + |
| 43 | + |
| 44 | +//promise |
| 45 | +// function database(id,database){ |
| 46 | +// return new Promise((resolve,reject)=>{ |
| 47 | +// setTimeout(()=>{ |
| 48 | +// console.log("data of",id) |
| 49 | +// resolve("success") |
| 50 | +// if(database){ |
| 51 | +// database() |
| 52 | +// } |
| 53 | +// },5000)}) |
| 54 | +// } |
| 55 | + |
| 56 | +function getdata(id){ |
| 57 | + return new Promise((resolve,reject)=>{ |
| 58 | + setTimeout(()=>{ |
| 59 | + console.log("data ",id) |
| 60 | + resolve("success") |
| 61 | + },3000) |
| 62 | + |
23 | 63 | }) |
| 64 | +} |
| 65 | + |
| 66 | +getdata(1).then((res)=>{ |
| 67 | + return getdata(2) |
| 68 | +}).then((res)=>{ |
| 69 | + return getdata(3) |
| 70 | +}).then((res)=>{ |
| 71 | + console.log("success") |
24 | 72 | }) |
25 | 73 |
|
| 74 | + |
| 75 | + |
| 76 | + |
26 | 77 |
|
0 commit comments