在 Javascript 中查找多个数组之间的差异

Question

I'm trying to write a function that takes multiple arrays and returns an array of all elements that are found in only one of the arrays. For example: ([1, 2, 3], [1, 2, 3], [1, 2, 3, 4]) returns [4] and ([1, 2, 3], [1, 2, 3], [1, 2, 3, 4], [5], [6]) returns [4, 5, 6])

I'm also trying to solve the problem without using any libraries such as lodash. I don't know if I'm on the right lines with below. Any help much appreciated.

const difference = (...arrays) => {
  return arrays.reduce((acc, cur) => acc.filter(ele => !cur.includes(ele)))
 }
         

Answer 1

You could check if the index is equal to the last index of a flat array.

 const difference = (...arrays) => arrays .flat() .filter((v, _, a) => a.indexOf(v) === a.lastIndexOf(v)); console.log(difference([1, 2, 3], [1, 2, 3], [1, 2, 3, 4])); // [4] console.log(difference([1, 2, 3], [2, 4], [5, 7])); // [1, 3, 4, 5, 7]