find sock pairs between socks array

sockPairs.js

function sockMerchant(n, ar) {
    // create color hash
    const colors = {};
    // count total matches (pairs)
    let matches = 0;
    ar.forEach(x => {
      // if color with truthy value exist, increment pairs by 1 and set color to zero to make it falsy
      if (colors[x]) {
      	matches++;
        colors[x] = 0
      }
      // if color value is falsy (0 or have no key inside hash), create or add 1
      else {
      	colors[x] = 1
      }
    })
  
  // result of socks pair
  return matches
}