src/client.js

const socketProtocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
const socketUrl = `${socketProtocol}//${window.location.host}`;
const socket = new WebSocket(socketUrl);

socket.onmessage = (event) => {
    term.write(event.data);

}

var term = new window.Terminal({
    cursorBlink: true
});
term.open(document.getElementById('terminal'));

function init() {
    if (term._initialized) {
        return;
    }

    term._initialized = true;

    term.prompt = () => {
        runCommand('\n');
    };
    setTimeout(() => {
        term.prompt();
    }, 300);

    term.onKey(keyObj => {
        runCommand(keyObj.key);
    });

    term.attachCustomKeyEventHandler((e) => {
        if ((e.ctrlKey || e.metaKey) && e.key === 'v') {
            navigator.clipboard.readText().then(text => {
                runCommand(text);
            });
            return false;
        }
        return true;
    });
}

function runCommand(command) {
    socket.send(command);

}

init();