JSFiddle - React, Tailwind, and code Playground

JavaScript

var unique = [];

myArray = [1,4,5,1,5];
myArray.sort();

for (var i=0, j;i<myArray.length;i = j) {
    for (j=i+1;j<myArray.length && myArray[i] === myArray[j]; j++);

    if (j == i + 1) {
        unique.push(myArray[i]);
    }
}

console.log(unique);