Editing JS 解析 JWT Token 信息

<!DOCTYPE html>
<html>

<head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta charset="utf-8" />
    <title>JS 解析 JWT Token 信息</title>
</head>

<body>
    <textarea placeholder="粘贴 JWT Token"></textarea>
</body>

</html>

textarea {
    width: 90vw;
    height: 90vh;
    font-size: 1.5em;
}

document.querySelector("textarea").oninput = function () {
    try {
        let json = parseJwt(this.value);
        this.value = JSON.stringify(json, null, 2);
    } catch (ex) {
        console.debug(ex);
        this.value = `${ex}`;
    }
}

function parseJwt(token) {
    var base64Url = token.split('.')[1];
    var base64 = base64Url.replace(/-/g, '+').replace(/_/g, '/');
    var jsonPayload = decodeURIComponent(atob(base64).split('').map(function (c) {
        return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2);
    }).join(''));

    return JSON.parse(jsonPayload);
};