JavaScript - base64 with Unicode support

In this short article, we would like to show how to encode text to base64 and back (decode base64) in JavaScript with Unicode support.

Quick solution (safe approach):

// ONLINE-RUNNER:browser;

var toUtf8 = function(text) {
  	var surrogate = encodeURIComponent(text);
  	var result = '';
    for (var i = 0; i < surrogate.length;) {
        var character = surrogate[i];
		i += 1;
        if (character == '%') {
        	var hex = surrogate.substring(i, i += 2);
			if (hex) {
				result += String.fromCharCode(parseInt(hex, 16));
			}
        } else {
        	result += character;
        }
    }
    return result;
};

var fromUtf8 = function(text) {
  	var result = '';
    for (var i = 0; i < text.length; ++i) {
        var code = text.charCodeAt(i);
        result += '%';
        if (code < 16) {
          	result += '0';
        }
        result += code.toString(16);
    }
    return decodeURIComponent(result);
};

var Base64 = {
    encode: function(text) {
        return btoa(toUtf8(text));
    },
    decode: function(base64) {
        return fromUtf8(atob(base64));
    }
};


// Example:

console.log(Base64.encode('This is text...'));      // VGhpcyBpcyB0ZXh0Li4u
console.log(Base64.decode('VGhpcyBpcyB0ZXh0Li4u')); // This is text...

console.log(Base64.encode('日本'));      // 5pel5pys
console.log(Base64.decode('5pel5pys')); // 日本

console.log(Base64.encode('I ❤️ JS'));          // SSDinaTvuI8gSlM=
console.log(Base64.decode('SSDinaTvuI8gSlM=')); // I ❤️ JS

Web browser methods based approach

Note: escape and unescape methods are marked as not recommended to use so read about them here and here.

// ONLINE-RUNNER:browser;

var toUtf8 = function(text) {
  	return unescape(encodeURIComponent(text));
};

var fromUtf8 = function(text) {
  	return decodeURIComponent(escape(text));
};

var Base64 = {
    encode: function(text) {
      	return btoa(toUtf8(text));
    },  
  	decode: function(base64) {
        return fromUtf8(atob(base64));
    }
};


// Example:

console.log(Base64.encode('This is text...'));      // VGhpcyBpcyB0ZXh0Li4u
console.log(Base64.decode('VGhpcyBpcyB0ZXh0Li4u')); // This is text...

console.log(Base64.encode('日本'));      // 5pel5pys
console.log(Base64.decode('5pel5pys')); // 日本

console.log(Base64.encode('I ❤️ JS'));          // SSDinaTvuI8gSlM=
console.log(Base64.decode('SSDinaTvuI8gSlM=')); // I ❤️ JS

See also

1. JavaScript - strings default encoding

References

1. btoa - MDN docs
2. base64.js - NPM Page