javascript - Rx.Observable.bindCallback 在 rxjs 中的作用域

Question

在 rxjs 4.x 中，Rx.Observable.fromCallback 似乎接受范围作为第二个参数，但在 5.0 中，此方法更改为 Rx.Observable.bindCallback 并且不接受范围参数。如何在 bindCallback 中添加范围参数。例如在 ES6 中。

class Test {
  constructor(input) {
    this.input = input;
  }

  callback(cb) {
    return cb(this.input);
  }

  rx() {
    // this works on rx 4.x
    // var observable = Rx.Observable.fromCallback(this.callback, this)();

    // this doesn't work, because this.callback function doesn't use original this, so cannot get this.input
    var observable = Rx.Observable.bindCallback(this.callback)();

    // Work around: Rx.Observable.bindCallback(this.callback)();
    // var me = this;
    // var observable = Rx.Observable.bindCallback((cb) => {me.callback(cb);})();

    observable.subscribe(
      input => console.log('get data => ' + input),
      err => console.log('get error =>' + err),
      () => console.log('complete')
    );
   }
  }

  new Test(100).rx();

Answer 1

在 http://reactivex.io/rxjs/class/es6/Observable.js~Observable.html#static-method-bindCallback 有一个例子它显示了如何执行此操作。

Use bindCallback on object method

const boundMethod = Rx.Observable.bindCallback(someObject.methodWithCallback);
boundMethod.call(someObject) // make sure methodWithCallback has access to someObject
.subscribe(subscriber);

你可以在不声明变量的情况下立即调用它，也可以像这样传递参数:

Rx.Observable.bindCallback(someObject.callback).call(someObject,<args>)

所以要绑定(bind)到this，你可以简单地调用

Rx.Observable.bindCallback(this.callback).call(this,<args>)