programming-examples/js/Functions/Write a JavaScript function to get all possible subset with a fixed length (for example 2) combinations in an array..js

function subset(arra, arra_size)  
 {  
    var result_set = [],   
        result;  
      
     
for(var x = 0; x < Math.pow(2, arra.length); x++)  
  {  
    result = [];  
    i = arra.length - 1;   
     do  
      {  
      if( (x & (1 << i)) !== 0)  
          {  
             result.push(arra[i]);  
           }  
        }  while(i--);  
  
    if( result.length >= arra_size)  
       {  
          result_set.push(result);  
        }  
    }  
  
    return result_set;   
}  
  
console.log(subset([1, 2, 3], 2));