Remove duplicates from multidimensional arrays (JS)

Question

I have two arrays with times and I want to remove the duplicates, the arrays could look like this:

arr1 = [ ['11:00','12:00','13:00'] ]
arr2 = ['11:00'],['13:00']

so I've tried to first loop through the second array with 2 for loops like this:

for (i = 0; i < timeslotsBusy.length; i++) {
  for (j = 0; j < timeslotsBusy[i].length; j++) {
    console.log(timeslotsBusy[i][j]);
  }
}

which gives me the values: 11:00, 13:00

now I have tried to go with a while loop a splice the array if the values match, but this didn't work very well. I also tried the filter method, but with no success

for (i = 0; i < timeslotsBusy.length; i++) {
  for (j = 0; j < timeslotsBusy[i].length; j++) {
    for (x = 0; x < timeslotsFree.length; x++) {
      timeslotsFree = timeslotsFree[x]
      timeslotsFree = timeslotsFree.filter(val => timeslotsBusy[i][j].includes(val))
    }
  }
}

Answer 1

• The input array (arr1, arr2) are multi-dimensional arrays so it is needed to make them to 1d array using Array.prototype.flat() function.

• After making it to 1d array, you can get the unduplicated members using Array.prototype.filter function. (To check if the arr2 includes the item or not, you can use Array.prototype.includes function.).

const arr1 = [ ['11:00','12:00','13:00'] ];
const arr2 = [ ['11:00'],['13:00'] ];

const arr1Flat = arr1.flat();
const arr2Flat = arr2.flat();

const output = arr1Flat.filter((item) => !arr2Flat.includes(item));
console.log(output);