arr.reduce
JavaScript
var arr = [1, 2, 3, 4, 5];
var initialValue = [];
var reducer = function(accum, item) {
if (item > 2 && accum.indexOf(item) < 0) {
accum.push(item);
}
return accum;
}
var result = arr.reduce(reducer, initialValue);
console.log(result);