let array1 = [1, 2, 3, 4, 5];

let array2 = [2, 3, 5, 7, 11];

let array3 = [3, 5, 7, 13, 17];

​

let commonElements = [];

​

for (let i = 0; i < array1.length; i++) {

  for (let j = 0; j < array2.length; j++) {

    for (let k = 0; k < array3.length; k++) {

      if (array1[i] === array2[j] && array2[j] === array3[k]) {

        if (!commonElements.includes(array1[i])) {

          commonElements.push(array1[i]);

        }

      }

    }

  }

}

​

console.log(commonElements);

​