code: function unique (elements) {
    for (var i = 0; i < elements.length - 1; i++) {
      for (var j = i + 1; j < elements.length; j++) {
        if (elements[i] === elements[j]) return false
      }
    }
  
    return true
  }
docs: Check if given elements are unique
  
  @param {Array} elements
  
  @returns {Boolean}