javascript - Get X numbers from arrayA[5000] into arrayB[] in groups -

i have array this:

 arraya = [1,2,3,4,5,6,7,8,9,1,2,3,4,5,6,7,8,9,1,2]; 

i need separated numbers in groups this:

arrayb = [1234,5678,9123,4567,8912]; 

as can see same arraya in groups of 4 values new numbers.

i able make work bug this: arrayb=[undefined1234,undefined5678]; code:

for (var = 0; < 20; i++) {         if (i/4== n+1){             arrayb[n] = temp;             n++;         }          temp += arraya[i]; } 

and thats it. understand bug, because of += not sure how other way.

this code trick

        var arraya = [1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 2,3,4];         var arrayb = [];         (var x = 0; x < arraya.length; x += 4) {            arrayb.push(arraya.slice(x, x + 4).join(''));         }          console.log(arrayb);   

update
millie has raised fair point. if need numbers in result array, use following statement in for loop

arrayb.push(parseint(arraya.slice(x, x + 4).join('')));