[bit-map] a demo of bit map #snippet

bit-map.js

const BitMap = function () {
  this.data = [];
};

BitMap.prototype.getIdx = num => parseInt(num / 32);
BitMap.prototype.getPos = num => num % 32;

BitMap.prototype.add = function (num) {
  const index = this.getIdx(num);
  const pos = this.getPos(num);

  if (this.data[index] === undefined) this.data[index] = 0;
  this.data[index] |= Math.pow(2, pos);
};

BitMap.prototype.exist = function (num) {
  const index = this.getIdx(num);
  const pos = this.getPos(num);
          
  return !!(this.data[index] && (this.data[index] & Math.pow(2, pos)));
};

const bitMap = new BitMap();
bitMap.add(1);
bitMap.add(5);
bitMap.add(45);
bitMap.add(95);
console.log(bitMap.data);
for (let i = 0; i < 96; i++) console.log(i, bitMap.exist(i));