Function to check if array is unique

isArrayUnique

function isUnique(array) {
    const u = {};
    let isUnique = 1;
    for (let i = 0, l = array.length; i < l; ++i) {
        if (u.hasOwnProperty(array[i])) {
            isUnique = 0;
            break;
        }
        u[array[i]] = 1;
    }
    return isUnique;
}