将额外参数传递给回调函数

Question

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.

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

我还有一个函数processMagic,它有两个参数:magic和theAnswer.

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

我想将函数processMagic作为参数传递给callWithMagic,但我也希望42将第二个参数传递theAnswer给processMagic.我怎样才能做到这一点？

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

Answer 1

只需创建一个包装回调:

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

或使用ECMAScript 6 箭头功能:

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