Simple Game Loop in JavaScript

game-loop.js

let previousTime = 0.0;
let isGameRunning = true;

const update = (diff) => {
    console.log(diff);
};
const render = () => { };

const loop = time => {
    const dt = time - previousTime;
    previousTime = time;
    update(dt);
    render();
    isGameRunning && window.requestAnimationFrame(loop);
};

// Launch
window.requestAnimationFrame(time => {
    previousTime = time;
    window.requestAnimationFrame(loop);
});

document.addEventListener("DOMContentLoaded", (event) => {
    document.getElementById("pause").addEventListener("click", (event) => {
        event.preventDefault();
        isGameRunning = false;
    });
    document.getElementById("play").addEventListener("click", (event) => {
        event.preventDefault();
        isGameRunning = true;
        window.requestAnimationFrame(loop);
    });
});