Added jwtDecode function

src/jwt.ts

@@ -0,0 +1,15 @@
+import {JSONAttemptParse} from './objects.ts';
+
+/**
+ * Decode a JWT payload, this will not check for tampering so be careful
+ *
+ * @param {string} token JWT to decode
+ * @return {unknown} JWT payload
+ */
+function decodeJwt<T>(token: string): T {
+	const base64 = token.split('.')[1]
+		.replace(/-/g, '+').replace(/_/g, '/');
+	return <T>JSONAttemptParse(decodeURIComponent(window.atob(base64).split('').map(function(c) {
+		return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2);
+	}).join('')));
+}