13.6.3 - 串联请求

先获取token，再根据token获取用户信息

// html
<button id="btn">获取用户信息</button>

import axios from "axios"
import { from, fromEvent } from "rxjs"
import { pluck, concatMap } from "rxjs/operators"
const button = document.getElementById("btn")
fromEvent(button, "click")
    .pipe(
    concatMap(event =>
              from(axios.get("http://localhost:3005/token")).pipe(
        pluck("data", "token")
    )
             ),
    concatMap(token =>
              from(axios.get("http://localhost:3005/userInfo")).pipe(pluck("data"))
             )
)
.subscribe(console.log)