JavaScript中的链函数 [英] Chain functions in JavaScript

问题描述

有没有一种方法可以链接JavaScript中的函数，因此当调用链中的最后一个函数时，我们会考虑指定的链中的所有函数. 基本上我想做的是同一件事 express-validator 做: 像这样:

Is there a way to chain functions in JavaScript so when last function in chain is called we take into consideration all function in chain that was specified. Basically what I am trying to do is the same thing express-validator does: Something like this:

check('password').passwordValidator().optional();

我希望能够打电话

check('password').passwordValidator();

和

check('password').passwordValidator().optional();

推荐答案

因此，您正在寻找一种

So you're looking for a sort of builder pattern? You can do that like this:

class Foo {
  _passwordValidator = false;
  _optional = false;

  passwordValidator() {
    this._passwordValidator = true;
    return this;
  }
  optional() {
    this._optional = true;
    return this;
  }

  doThing() {
    if (this._optional) { /* ... */ }
    if (this._passwordValidator) { /* ... */ }
  }
}

const foo = new Foo().passwordValidator().optional();

foo.doThing();

要更直接地回答您的问题，在当前方法调用链完成之前，没有办法等待做某事；您必须在示例中调用类似doThing()的方法，以表明您实际上现在想做这件事.

to more directly answer your question, there is no way to wait to do something until the current chain of method calls is done; you have to call a method like doThing() in the example to signal that you actually want to do the thing now.

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