rxjs - 属性 'filter'在 'BehaviorSubject'类型上不存在。在rxjs 6中

Question

将Rx js从5升级到6时，抛出以下错误

[ts]类型'BehaviorSubject'上不存在属性'filter'。

当前行为

import {BehaviorSubject} from 'rxjs';

tokenSubject: BehaviorSubject<string> = new BehaviorSubject<string>(null);
return this.tokenSubject
                .filter(token => token != null)
                .take(1)
                .switchMap(token => {
                    return next.handle(this.addToken(req));
                });

[ts]类型'BehaviorSubject'上不存在属性'filter'。

环境

 "@angular/common": "^6.0.3",
   "rxjs": "^6.0.0",

预期行为

没有错误，工作正常

以前的行为

import { BehaviorSubject } from "rxjs/BehaviorSubject";
tokenSubject: BehaviorSubject<string> = new BehaviorSubject<string>(null);
return this.tokenSubject
                .filter(token => token != null)
                .take(1)
                .switchMap(token => {
                    return next.handle(this.addToken(req));
                });

[ts]类型'BehaviorSubject'上不存在属性'filter'。

环境

"@angular/common": "^5.0.3",
  "rxjs": "^5.4.3"

Answer 1

RxJS v5.x to v6 Update Guide
说:

The previous coding style of chaining operators has been replaced by piping the result of one operator to another.

使用管道语法:

return this.tokenSubject.pipe(
    filter(token => token != null),
    take(1),
    switchMap(token => {
        return next.handle(this.addToken(req));
    })
);