What algorithm would you recommend for finding the difference between two arrays?

Question

JavaScript

Good day.
There was a need to create a function in JS, which:

• receives at the input: two arrays (1st original, 2nd modified)
  
• at the output: the ordinal number of a different element and the type of difference
  
• input arrays in turn consist of an array with two elements
  
• types of difference:
  1. 1 element added (always to the end of the array)
  2. 1 element removed
  3. 1 element changed
  

What is available:

function func(a,b){
  // Если старый массив короче значит добавлен 1 элемент в конец массива
  if (b.length > a.length) {
    return {num: b.length - 1, type: 'add'};
  }
  
  // Если старый массив длинее значит удалён 1 элемент
  else if (b.length < a.length) {
    for (let i = 0; i < a.length; i++) {
      if (a[i][0] != b[i][0] || a[i][1] != b[i][1]) {
        return {num: i, type: 'delete'};
      }
    }
    
  // Иначе был изменён элемент
  } else {
    for (let i = 0; i < a.length; i++) {
      if (a[i][0] != b[i][0] || a[i][1] != b[i][1]) {
        return {num: i, type: 'change'};
      }
    }
  }
}

Does anyone know a better algorithm?
I will be very grateful.
JsFiddle:

Answer 1

Levenshtein distance