如何保存对Array方法的引用？

Question

有没有办法实现这种行为？

谢谢。

const filterBy = (arr, side) => {
    const reduceFunc = side === 'left' ? reduce : reduceRight;

    arr.reduceFunc(...)
}

Answer 1

是的，您只需要获取一个字符串，然后使用括号表示法即可访问Array.prototype上的相应函数：

const filterBy = (arr, side) => {
  const propName = side === 'left' ? 'reduce' : 'reduceRight';
  
  // silly minimal example, will simply return the last item that's iterated over:
  return arr[propName]((a, item) => item);
}
const arr = [1, 2];

// Reduces starting from left, last item iterated over will be 2:
console.log(filterBy(arr, 'left'));
// Reduces starting from right, last item iterated over will be 1:
console.log(filterBy(arr, 'right'));