将一个额外的参数传递给回调函数 [英] Pass an extra argument to a callback function

问题描述

我有一个函数 callWithMagic ，它将一个回调函数作为参数并用一个参数调用它。

I have a function callWithMagic which takes a callback function as a parameter and calls it with one argument.

const callWithMagic = callback => {
  const magic = getMagic();
  callback(magic);
};

我也有一个函数 processMagic 两个参数： magic 和 theAnswer 。

I also have a function processMagic which takes two arguments: magic and theAnswer.

const processMagic = (magic, theAnswer) => {
  someOtherMagic();
};

我想将函数 processMagic 传递为 callWithMagic 的一个参数，但我也想传递 42 作为第二个参数（ theAnswer ）到 processMagic 。如何才能做到这一点？

I want to pass the function processMagic as an argument to callWithMagic, but I also want to pass 42 as the second parameter (theAnswer) to processMagic. How can I do that?

callWithMagic(<what should I put here?>);

推荐答案

只需创建一个包装回调：

Just create a wrapper callback:

callWithMagic(function(magic) {
  return processMagic(magic, 42);
});

或者使用ECMAScript  6 arrow functions ：

Or using ECMAScript 6 arrow functions:

callWithMagic(magic => processMagic(magic, 42));

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