My first permutation algorithm

permutation.js

var data = [];
permutation = (arr, prefix = []) => {
    if(arr.length == 2){
        let comb1 = [...prefix],
            comb2 = [...prefix];
        comb1.push(arr[0]);
        comb1.push(arr[1]);
        data.push(comb1);
        comb2.push(arr[1]);
        comb2.push(arr[0]);
        data.push(comb2);
    }
    for(let i = 0; i < arr.length; i++){
        let current = [...prefix];
        current.push(arr[i]);
        let arr_temp = [...arr];
        arr_temp.splice(i, 1);
        permutation(arr_temp, current);
    }
}
permutation([1,2,3,4,5,6,7,8]);