[RxJS] Transformation operator: buffer, bufferCount, bufferTime

RxJS缓冲操作符详解

最新推荐文章于 2022-01-05 14:37:39 发布

转载最新推荐文章于 2022-01-05 14:37:39 发布 · 89 阅读

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原文链接：http://www.cnblogs.com/Answer1215/p/5535668.html

本文详细介绍了RxJS中的缓冲操作符buffer及其变体bufferTime、bufferCount的使用方法。通过具体的示例代码展示了如何利用这些操作符来按特定条件组合连续的数据项，并将输出作为数组发射。

This lesson will teach you about another horizontal combination operator: buffer and its variants. Buffer groups consecutive values together, emitting the output as an array. The buffer variants and their arguments allow to specify when to close the buffers.

buffer(close observable): According to another observalbe to group items.

var foo = Rx.Observable.of('h', 'e', 'l', 'l', 'o')
  .zip(Rx.Observable.interval(600).take(5), (x,y) => x);
var bar = Rx.Observable.interval(900).take(3);

/*
-----h-----e-----l-----l-----o|       (foo)
--------0--------1--------2|          (bar)

        buffer(bar)

--------h--------e--------ll|
*/

var result = foo.buffer(bar);

result.subscribe(
  function (x) { console.log('next ' + x); },
  function (err) { console.log('error ' + err); },
  function () { console.log('done'); },
);
  
  /*

"next h"
"next e"
"next l,l"
"done"
  
  */

bufferTime(number):

var foo = Rx.Observable.of('h', 'e', 'l', 'l', 'o')
  .zip(Rx.Observable.interval(600).take(5), (x,y) => x);

/*
-----h-----e-----l-----l-----o|       (foo)
--------x--------x--------x|          (900ms)

        bufferTime(900)

--------h--------e--------ll|
*/

var result = foo.bufferTime(900);

result.subscribe(
  function (x) { console.log('next ' + x); },
  function (err) { console.log('error ' + err); },
  function () { console.log('done'); },
);
  
  /*

"next h"
"next e"
"next l,l"
"done"
  
  */

bufferCount(number):

var foo = Rx.Observable.of('h', 'e', 'l', 'l', 'o')
  .zip(Rx.Observable.interval(600).take(5), (x,y) => x);

/*
-----h-----e-----l-----l-----o|       (foo)

        bufferCount(2)

----------([h,e])------([l,l])([o|])l
*/

var result = foo.bufferCount(2);

result.subscribe(
  function (x) { console.log('next ' + x); },
  function (err) { console.log('error ' + err); },
  function () { console.log('done'); },
);
  
  /*

"next h,e"
"next l,l"
"next o"
"done"
  
  */

转载于:https://www.cnblogs.com/Answer1215/p/5535668.html