How do i remove two of the same item from an array [closed]

Question

im working my way through the odin project and looking at for loops and different methods. Im trying to find a way to pass this test :

test('removes multiple of the same value', () => {
expect(removeFromArray([1, 2, 2, 3], 2)).toEqual([1, 3]);
});

I know you can remove a duplicate using filter and Sets but how do i remove both the 2's in the array so i end up with [1, 3]

I know this is probably simple but its just where im upto at the moment.

Answer 1

You can iterate twice over the array. In the first iteration, you count the occurrences of the elements and in the second iteration you remove elements with occurrence > 1.

Answer 2

function removeFromArray(arr) {

   if(!arr || !arr.length){
      return [];
   }
   const remElem = {};

   const all = arr.reduce((all,cur) => {
   if(!all[cur]) {
      all[cur] = true;
   } else {
      remElem[cur] = true;
   }
      return all;
   }, {}) ;

   return Object.keys(all)
      .filter((cur) => !remElem[cur])
      .map((cur) => Number(cur));
} 

Wrote on cellphone, cant test, please test, it should work :)

Added: Stackblitz Demo

Answer 3

Ok I came up with this :

const array = [1, 2, 2, 3];

function removeFromArray(){
 
let uniqueArray = [...new Set(array)];
uniqueArray.splice(1,1);
return uniqueArray;

  
}

removeFromArray();

It passed the test.Not sure its the right way to do things but it works and i understand it so thats a bonus.

Jabaa, thanks for your prompt. Sometime with JS I just cant think straight.