[Solved-5 Solutions] Encode a string to Base64 in javascript - javascript tutorial
Problem:
How to encode a string to Base64 in javascript ?
Solution 1:
We can use btoa() and atob() to convert to and from base64 encoding.
- btoa() accepts a “string” where each character represents an 8-bit byte - If we pass a string containing characters that can’t be represented in 8 bits, it will probably break. This isn’t a problem if you’re actually treating the string as a byte array, but if you’re trying to do something else then you’ll have to encode it first.
- atob() returns a “string” where each character represents an 8-bit byte - Its value will be between 0 and 0xff. This does not mean it’s ASCII - probably if you’re using this function at all, we expect to be working with binary data and not text.
Solution 2:
We can use btoa (to base-64) and atob (from base-64). For IE 9 and below, try the jquery-base64 plugin:
$.base64.encode("this is a test");
$.base64.decode("dGhpcyBpcyBhIHRlc3Q=");
Solution 3:
Internet Explorer 10+
// Define the string
var string = 'Hello World!';
// Encode the String
var encodedString = btoa(string);
console.log(encodedString); // Outputs: "SGVsbG8gV29ybGQh"
// Decode the String
var decodedString = atob(encodedString);
console.log(decodedString); // Outputs: "Hello World!"
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// Create Base64 Object
var Base64={_keyStr:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",encode:function(e){var t="";var n,r,i,s,o,u,a;var f=0;e=Base64._utf8_encode(e);while(f<e.length){n=e.charCodeAt(f++);r=e.charCodeAt(f++);i=e.charCodeAt(f++);s=n>>2;o=(n&3)<<4|r>>4;u=(r&15)<<2|i>>6;a=i&63;if(isNaN(r)){u=a=64}else if(isNaN(i)){a=64}t=t+this._keyStr.charAt(s)+this._keyStr.charAt(o)+this._keyStr.charAt(u)+this._keyStr.charAt(a)}return t},decode:function(e){var t="";var n,r,i;var s,o,u,a;var f=0;e=e.replace(/[^A-Za-z0-9\+\/\=]/g,"");while(f<e.length){s=this._keyStr.indexOf(e.charAt(f++));o=this._keyStr.indexOf(e.charAt(f++));u=this._keyStr.indexOf(e.charAt(f++));a=this._keyStr.indexOf(e.charAt(f++));n=s<<2|o>>4;r=(o&15)<<4|u>>2;i=(u&3)<<6|a;t=t+String.fromCharCode(n);if(u!=64){t=t+String.fromCharCode(r)}if(a!=64){t=t+String.fromCharCode(i)}}t=Base64._utf8_decode(t);return t},_utf8_encode:function(e){e=e.replace(/\r\n/g,"\n");var t="";for(var n=0;n<e.length;n++){var r=e.charCodeAt(n);if(r<128){t+=String.fromCharCode(r)}else if(r>127&&r<2048){t+=String.fromCharCode(r>>6|192);t+=String.fromCharCode(r&63|128)}else{t+=String.fromCharCode(r>>12|224);t+=String.fromCharCode(r>>6&63|128);t+=String.fromCharCode(r&63|128)}}return t},_utf8_decode:function(e){var t="";var n=0;var r=c1=c2=0;while(n<e.length){r=e.charCodeAt(n);if(r<128){t+=String.fromCharCode(r);n++}else if(r>191&&r<224){c2=e.charCodeAt(n+1);t+=String.fromCharCode((r&31)<<6|c2&63);n+=2}else{c2=e.charCodeAt(n+1);c3=e.charCodeAt(n+2);t+=String.fromCharCode((r&15)<<12|(c2&63)<<6|c3&63);n+=3}}return t}}
// Define the string
var string = 'Hello World!';
// Encode the String
var encodedString = Base64.encode(string);
console.log(encodedString); // Outputs: "SGVsbG8gV29ybGQh"
// Decode the String
var decodedString = Base64.decode(encodedString);
console.log(decodedString); // Outputs: "Hello World!"
Here how to encode normal text to base64 in Node.js:
//Buffer() requires a number, array or string as the first parameter, and an optional encoding type as the second parameter.
// Default is utf8, possible encoding types are ascii, utf8, ucs2, base64, binary, and hex
var b = new Buffer('JavaScript');
// If we don't use toString(), JavaScript assumes we want to convert the object to utf8.
// We can make it convert to other formats by passing the encoding type to toString().
var s = b.toString('base64');
How to decode base64 encoded strings:
var b = new Buffer('SmF2YVNjcmlwdA==', 'base64')
var s = b.toString();
To encode an array of bytes using dojox.encoding.base64:
var str = dojox.encoding.base64.encode(myByteArray);
To decode a base64-encoded string:
var bytes = dojox.encoding.base64.decode(str)
bower install angular-base64
<script src="bower_components/angular-base64/angular-base64.js"></script>
angular
.module('myApp', ['base64'])
.controller('myController', [
'$base64', '$scope',
function($base64, $scope) {
$scope.encoded = $base64.encode('a string');
$scope.decoded = $base64.decode('YSBzdHJpbmc=');
}]);
Solution 4:
- There's a bugs in both implementations of _utf8_decode. c1 and c2 are assigned as global variables due to broken use of the var statement, and c3 is not initialized or declared at all.
- It works, but these variables will overwrite any existing ones with the same name outside this function.
// private method for UTF-8 decoding
_utf8_decode : function (utftext) {
var string = "";
var we = 0;
var c = 0, c1 = 0, c2 = 0;
while ( we < utftext.length ) {
c = utftext.charCodeAt(i);
if (c < 128) {
string += String.fromCharCode(c);
i++;
}
else if((c > 191) && (c < 224)) {
c1 = utftext.charCodeAt(i+1);
string += String.fromCharCode(((c & 31) << 6) | (c1 & 63));
we += 2;
}
else {
c1 = utftext.charCodeAt(i+1);
c2 = utftext.charCodeAt(i+2);
string += String.fromCharCode(((c & 15) << 12) | ((c1 & 63) << 6) | (c2 & 63));
we += 3;
}
}
return string;
}
Solution 5:
Use this solution:
base64.encode(/* String */);
base64.decode(/* String */);
utf8.encode(/* String */);
utf8.decode(/* String */);