let encodeEmail = function(email) {
	let byteArray = [];
	for(i =0; i < email.length; i++) {
		byteArray.push(email.charCodeAt(i));
	}
	return encodeURIComponent(byteArray.toString());
}

let decodeEmail = function(encodedEmail) {
	let byteArray = decodeURIComponent(encodedEmail).split(',');
	let email = String.fromCharCode(...byteArray);

	return email;
}


let email = 'test.のコンサ@abc.com';
console.log(encodeEmail(email)); //116%2C101%2C115%2C116%2C46%2C12398%2C12467%2C12531%2C12469%2C64%2C97%2C98%2C99%2C46%2C99%2C111%2C109​​​​​
console.log(decodeEmail(encodeEmail(email))); //test.のコンサ@abc.com