RxJS-将可观察对象一分为二,等待第一个完成

这似乎相当简单,因为 skipLast 和 takeLast 操作员:

const source = ...;

const first = source.skipLast(1);
const second = source.takeLast(1);

let Rx = require('rxjs/Rx');

let arr = ["a", "b", "c", "d", "e"]
let par = Rx.Observable.from(arr).partition((v, i) => i < arr.length - 1)
let res = Rx.Observable.concat(par[0], par[1])

res.subscribe(
    x => console.log('On Next: %s', x),
    e => console.log('On Error: %s', e),
    () => console.log('On Complete')
)