bbo/difference.js

bbo is a utility library of zero dependencies for javascript.

'use strict';

/**
 * Returns the difference between two arrays.
 * Create a Set from b, then use Array.prototype.
 * Filter() on a to only keep values not contained in b.
 */
function difference(a, b) {
  var s = new Set(b);
  return a.filter(x => !s.has(x));
}

module.exports = difference;