Promis.then()

 1     function cook() {
 2       console.log('開始做飯。');
 3       var p = new Promise(function (resolve, reject) {
 4         setTimeout(function () {
 5           console.log('做飯完畢！');
 6           resolve('雞蛋炒飯');
 7         }, 1000);
 8       });
 9       return p;
10     }
11 
12     function eat(data) {
13       console.log('開始吃飯：' + data);
14       var p = new Promise(function (resolve, reject) {
15         setTimeout(function () {
16           console.log('吃飯完畢!');
17           resolve('一塊碗和一雙筷子');
18         }, 2000);
19       });
20       return p;
21     }
22     function wash(data) {
23       console.log('開始洗碗：' + data);
24       var p = new Promise(function (resolve, reject) {
25         setTimeout(function () {
26           console.log('洗碗完畢!');
27           resolve('乾凈的碗筷');
28         }, 2000);
29       });
30       return p;
31     }
32 
33     cook()
34       .then(eat)
35       .then(wash)
36       .then(function (data) {
37         console.log(data);
38       });

輸出：

備註：resolve只能傳入一個參數，傳入的其它參數，讀取到的值為"undefined"。