JSは2つの配列の違いまたは同じ要素を取り出します.

getArrDifference(arr1, arr2) {

    return arr1.concat(arr2).filter(function(v, i, arr) {

        return arr.indexOf(v) === arr.lastIndexOf(v);

    });

},

getArrEqual(arr1, arr2) {
    let newArr = [];
    for (let i = 0; i < arr2.length; i++) {
        for (let j = 0; j < arr1.length; j++) {
            if(arr1[j] === arr2[i]){
                newArr.push(arr1[j]);
            }
        }
    }
    return newArr;
},