<script>
        var colors = ["#ccc","#333","#666"];
        var data = [
            { name: "Семен" },
            { name: "Роман" },
            { name: "Николай" },
            { name: "Аркадий" },
            { name: "Жорж" }
        ]
        var result = data.map((x,i)=>{return {...x, color: colors[i % colors.length]}})
    </script>