RxJS groupBy 和 combineAll 运算符似乎省略了输出 [英] RxJS groupBy and combineAll operators seem to omit output
本文介绍了RxJS groupBy 和 combineAll 运算符似乎省略了输出的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
当使用 .groupBy 和 .concatAll 组合对输出进行分组时,不会生成一些预期的输出.
When grouping output with the combination of .groupBy and .concatAll, some expected output is not generated.
示例代码:
var Rx = require('rx');
var source = Rx.Observable.from(['a1', 'a2', 'b1', 'b2', 'a3', 'a4', 'b3', 'b4'])
.groupBy(function (item) { return item.substr(0, 1); })
.concatAll();
var subscription = source.subscribe(
function (x) {
console.log('Next: %s', x);
},
function (err) {
console.log('Error: %s', err);
},
function () {
console.log('Completed');
});
实际输出:
$ node index.js
Next: a1
Next: a2
Next: a3
Next: a4
Completed
预期输出:
$ node index.js
Next: a1
Next: a2
Next: a3
Next: a4
Next: b1
Next: b2
Next: b3
Next: b4
Completed
我是否误解了这些运算符的工作原理?或者这是一个 RxJS 错误?(暂时在 https://github.com/Reactive-Extensions/RxJS/issues/1264.)
Am I misunderstanding how these operators work? Or is this an RxJS bug? (Tentatively filed as a bug already at https://github.com/Reactive-Extensions/RxJS/issues/1264.)
推荐答案
想通了.这是的问题热与冷 observables.如下更改代码使其按预期工作:
Figured it out. This is a problem of hot vs cold observables. Changing the code as follows makes it work as expected:
var source = Rx.Observable.from(['a1', 'a2', 'b1', 'b2', 'a3', 'a4', 'b3', 'b4'])
.groupBy(function (item) { return item.substr(0, 1); })
.map(function (obs) { // <<<<< ADD THIS .map clause to fix
var result = obs.replay();
result.connect();
return result;
})
.concatAll();
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