Bitwise Flags Class with example

gistfile1.js

class Flag {
  constructor() {
    this.value = 0;
  }
  
  add(flag) {
    this.value = this.value | flag;
  }

  remove(flag) {
    this.value = this.value & ~flag;
  }

  has(flag) {
    return !!(this.value & flag);
  }
}

// Flag constants are powers of 2.
const POSITIONS = {
  TOP: 1,
  LEFT: 2,
  BOTTOM: 4,
  RIGHT: 8
}

let myFlag = new Flag();

myFlag.add(POSITIONS.TOP | POSITIONS.LEFT);
console.log(myFlag.value);

console.log("TOP: " + myFlag.has(POSITIONS.TOP));
console.log("BOTTOM: " + myFlag.has(POSITIONS.BOTTOM));
console.log("RIGHT: " + myFlag.has(POSITIONS.RIGHT));
console.log("LEFT: " + myFlag.has(POSITIONS.LEFT));