console.log(getFlags(1023));

​

function getFlags(sum){

  var flags = [];

  //if we have no sum return empty array

  if(!sum){

    return flags;

  }

  //check if sum is odd

  if(sum % 2 !== 0){

    //remember flag

    flags.push(1);

    //minus this flag from sum

    sum--;

  }

  //get max exponent of 2 in our sum

  var k = Math.floor(Math.log2(sum));

  while(k >= 1){

    //get max flag

    var c = Math.pow(2, k);

    //remember it

    flags.push(c);

    //minus this flag from sum

    sum = sum - c;

    //recount max exponent of 2 in our sum

    k = Math.floor(Math.log2(sum));

  }

  return flags;

}