keepOnlyUniques.js

function solution(myArr) {
    var myArr = [9, 3, 9, 3, 9, 7, 9];
    var leng = myArr.length;
    var result = [];
    var leftObj = {};
    var i;

    for (i = 0; i < leng; i++) {
        leftObj[myArr[i]] = 0;
    }
    for (i in leftObj) {
        result.push(i);
    }
    console.log(result);
}
solution();