SOURCE

const input = [1, 2, 3];

const output = [[1],[2],[3],[1,2],[1,3],[2,3],[1,2,3]];


function composite(init, arr) {
  if(arr.length === 0) {
    return [];
  }
  
	let tmp = [];
	
  for(let i=0;i<arr.length;i++) {
    
    tmp.push([...init, arr[i]]);
    
    if(arr.length > 1&& i<arr.length-1) {
      tmp = [...tmp, ...composite([...init, arr[i]], arr.slice(i+1))];
       // tmp.push(composite([...init, arr[i]], arr.slice(i+1))); 
    }
  }

  return tmp;
  
}

const result = composite([], [1,2,3,4]);

console.log(result.slice());