// sever.js
    function cpuStats() {
        return new Promise((resolve) => {
            os.cpuUsage((value) => {
                let data = {
                    'cpu': (value * 100).toFixed(0),
                    'cpuCnt' : os.cpuCount(), 
                    'memory': memoryPer, // (os.freememPercentage() * 100).toFixed(2),
                    'memoryAva' : os.freemem(),
                    'memoryTot' : os.totalmem(),
                    'disk': usedInPercentage, //(os.totalmem() / 1024).toFixed(2)
                    'diskAva' : diskAvailable,
                    'diskTot' : diskTotal
                }
                resolve(data);
            })
        })
    }
    setInterval(() => {
        cpuStats()
            .then((data) => {
                console.log(data) // Testing
                socket.emit('serverData', data)
            })
    }, 5000);



    // client
    socket.on('serverData', data )=>{ 
        
        var cpu = document.getElementById('cpu');
        var memory = document.getElementById('memory');
        var disk = document.getElementById('disk');
        
        cpu.innerText = data.cpu;
        memory.innerText = data.memory;
        disk.innerText = data.disk;
        
    });

In server.js, I created an object called data using promise and then . on client-side I'm getting only this error: Uncaught SyntaxError: Malformed arrow function parameter list