复制
1const promise = new Promise((resolve, reject) => {
2  reject("error");
3  resolve("success2");
4});
5promise
6.then(res => {
7    console.log("then1: ", res);
8  }).then(res => {
9    console.log("then2: ", res);
10  }).catch(err => {
11    console.log("catch: ", err);
12  }).then(res => {
13    console.log("then3: ", res);
14  })