Node js throws btoa is not defined error

Question

In my node js application I did an npm install btoa-atob so that I could use the btoa   and atob   functions which are native in client-side javascript but for some reason weren t included in node  The new directory showed up in my node modules folder  which itself is in root alongside app js  Then I made sure to add btoa-atob as a dependency in my package json file which is in root  However  for some reason  it still will not work  console log btoa  quot Hello World  quot        should output  quot SGVsbG8gV29ybGQh quot  to the console  but instead  I get the error   btoa is not defined   Did I not do the install properly  What did I overlook

User · Answer

I found that although the shims from answers above worked, they did not match the behaviour of desktop browsers' implementations of btoa() and atob():

const btoa = function(str){ return Buffer.from(str).toString('base64'); }
// returns "4pyT", yet in desktop Chrome would throw an error.
btoa('?');
// returns "fsO1w6bCvA==", yet in desktop Chrome would return "fvXmvA=="
btoa(String.fromCharCode.apply(null, new Uint8Array([0x7e, 0xf5, 0xe6, 0xbc])));

As it turns out, Buffer instances represent/interpret strings encoded in UTF-8 by default. By contrast, in desktop Chrome, you can't even input a string that contains characters outside of the latin1 range into btoa(), as it will throw an exception: Uncaught DOMException: Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the Latin1 range.

Therefore, you need to explicitly set the encoding type to latin1 in order for your Node.js shim to match the encoding type of desktop Chrome:

const btoaLatin1 = function(str) { return Buffer.from(str, 'latin1').toString('base64'); }
const atobLatin1 = function(b64Encoded) {return Buffer.from(b64Encoded, 'base64').toString('latin1');}

const btoaUTF8 = function(str) { return Buffer.from(str, 'utf8').toString('base64'); }
const atobUTF8 = function(b64Encoded) {return Buffer.from(b64Encoded, 'base64').toString('utf8');}

btoaLatin1('?'); // returns "Ew==" (would be preferable for it to throw error because this is undecodable)
atobLatin1(btoa('?')); // returns "\u0019" (END OF MEDIUM)

btoaUTF8('?'); // returns "4pyT"
atobUTF8(btoa('?')); // returns "?"

// returns "fvXmvA==", just like desktop Chrome
btoaLatin1(String.fromCharCode.apply(null, new Uint8Array([0x7e, 0xf5, 0xe6, 0xbc])));
// returns "fsO1w6bCvA=="
btoaUTF8(String.fromCharCode.apply(null, new Uint8Array([0x7e, 0xf5, 0xe6, 0xbc])));

User · Answer

Here s a concise universal solution for base64 encoding   const nodeBtoa    b    gt  Buffer from b  toString  base64    export const base64encode   typeof btoa      undefined    btoa   nodeBtoa

User · Answer

The solutions posted here don t work in non-ascii characters  i e  if you plan to exchange base64 between Node js and a browser   In order to make it work you have to mark the input text as  binary     Buffer from  H  ll   w  rld      binary   toString  base64     This gives you SOlsbPMgd NybGQhIQ    If you make atob  SOlsbPMgd NybGQhIQ     in a browser it will decode it in the right way  It will do it right also in Node js via   Buffer from  SOlsbPMgd NybGQhIQ      base64   toString  binary     If you don t do the  binary part   you will decode wrongly the special chars   I got it from the implementation of the btoa npm package

User · Answer

Maybe you don t need it anymore but if someone needs this using node  https   www npmjs com package btoa

User · Answer

export const universalBtoa   str   gt      try       return btoa str       catch  err        return Buffer from str  toString  base64            export const universalAtob   b64Encoded   gt      try       return atob b64Encoded       catch  err        return Buffer from b64Encoded   base64   toString

User · Answer

The  btoa-atob  module does not export a programmatic interface  it only provides command line utilities   If you need to convert to Base64 you could do so using Buffer   console log Buffer from  Hello World    toString  base64       Reverse  assuming the content you re decoding is a utf8 string    console log Buffer from b64Encoded   base64   toString         Note  prior to Node v4  use new Buffer rather than Buffer from

User · Answer

I have a code shared between server and client and I needed an implementation of btoa inside it  I tried doing something like   const btoaImplementation    btoa     str   gt  Buffer from str  toString  base64       but the Server would crush with      ReferenceError  btoa is not defined   while Buffer is not defined on the client   I couldn t check window btoa  it s a shared code  remember    So I ended up with this implementation   const btoaImplementation   str   gt        try           return btoa str         catch err            return Buffer from str  toString  base64

User · Answer

Same problem with the  script  plugin in the Atom editor  which is an old version of node  not having btoa    nor atob    nor does it support the Buffer datatype   Following code does the trick    x000D   x000D  var Base64   new function     x000D    var keyStr    ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789     x000D    this encode   function input    x000D      var output       x000D      var chr1  chr2  chr3  enc1  enc2  enc3  enc4  x000D      var i   0  x000D      input   Base64  utf8 encode input   x000D      while  i  lt  input length    x000D        chr1   input charCodeAt i     x000D        chr2   input charCodeAt i     x000D        chr3   input charCodeAt i     x000D        enc1   chr1  gt  gt  2  x000D        enc2     chr1  amp  3   lt  lt  4     chr2  gt  gt  4   x000D        enc3     chr2  amp  15   lt  lt  2     chr3  gt  gt  6   x000D        enc4   chr3  amp  63  x000D        if  isNaN chr2     x000D          enc3   enc4   64  x000D          else if  isNaN chr3     x000D          enc4   64  x000D          x000D        output   output   keyStr charAt enc1    keyStr charAt enc2    keyStr charAt enc3    keyStr charAt enc4   x000D        x000D      return output  x000D      x000D   x000D    this decode   function input    x000D      var output       x000D      var chr1  chr2  chr3  x000D      var enc1  enc2  enc3  enc4  x000D      var i   0  x000D      input   input replace    A-Za-z0-9        g       x000D      while  i  lt  input length    x000D        enc1   keyStr indexOf input charAt i      x000D        enc2   keyStr indexOf input charAt i      x000D        enc3   keyStr indexOf input charAt i      x000D        enc4   keyStr indexOf input charAt i      x000D        chr1    enc1  lt  lt  2     enc2  gt  gt  4   x000D        chr2     enc2  amp  15   lt  lt  4     enc3  gt  gt  2   x000D        chr3     enc3  amp  3   lt  lt  6    enc4  x000D        output   output   String fromCharCode chr1   x000D        if  enc3    64    x000D          output   output   String fromCharCode chr2   x000D          x000D        if  enc4    64    x000D          output   output   String fromCharCode chr3   x000D          x000D        x000D      output   Base64  utf8 decode output   x000D      return output  x000D      x000D   x000D    this  utf8 encode   function string    x000D      string   string replace   r n g    n    x000D      var utftext       x000D      for  var n   0  n  lt  string length  n      x000D        var c   string charCodeAt n   x000D        if  c  lt  128    x000D          utftext    String fromCharCode c   x000D          else if   c  gt  127   amp  amp   c  lt  2048     x000D          utftext    String fromCharCode  c  gt  gt  6    192   x000D          utftext    String fromCharCode  c  amp  63    128   x000D          else   x000D          utftext    String fromCharCode  c  gt  gt  12    224   x000D          utftext    String fromCharCode   c  gt  gt  6   amp  63    128   x000D          utftext    String fromCharCode  c  amp  63    128   x000D          x000D        x000D      return utftext  x000D      x000D   x000D    this  utf8 decode   function utftext    x000D      var string       x000D      var i   0  x000D      var c   0  x000D        c1   0  x000D        c2   0  x000D        c3   0  x000D      while  i  lt  utftext length    x000D        c   utftext charCodeAt i   x000D        if  c  lt  128    x000D          string    String fromCharCode c   x000D          i    x000D          else if   c  gt  191   amp  amp   c  lt  224     x000D          c2   utftext charCodeAt i   1   x000D          string    String fromCharCode   c  amp  31   lt  lt  6     c2  amp  63    x000D          i    2  x000D          else   x000D          c2   utftext charCodeAt i   1   x000D          c3   utftext charCodeAt i   2   x000D          string    String fromCharCode   c  amp  15   lt  lt  12      c2  amp  63   lt  lt  6     c3  amp  63    x000D          i    3  x000D          x000D        x000D      return string  x000D      x000D      x000D   x000D  var btoa   Base64 encode  x000D  var atob   Base64 decode  x000D   x000D  console log  btoa  A         btoa  A     x000D  console log  btoa  QQ           atob  QQ       x000D  console log  btoa  B         btoa  B     x000D  console log  btoa  Qg           atob  Qg       x000D   x000D   x000D

User · Answer

My team ran into this problem when using Node with React Native and PouchDB  Here is how we solved it     NPM install buffer     npm install --save buffer   Ensure Buffer  btoa  and atob are loaded as a globals   global Buffer   global Buffer    require  buffer   Buffer   if  typeof btoa      undefined       global btoa   function  str        return new Buffer str   binary   toString  base64            if  typeof atob      undefined       global atob   function  b64Encoded        return new Buffer b64Encoded   base64   toString  binary

User · Answer

I understand this is a discussion point for a node application  but in the interest of universal JavaScript applications running on a node server  which is how I arrived at this post  I have been researching this for a universal   isomorphic react app I have been building  and the package abab worked for me  In fact it was the only solution I could find that worked  rather than using the Buffer method also mentioned  I had typescript issues     This package is used by jsdom  which in turn is used by the window package    Getting back to my point  based on this  perhaps if this functionality is already written as an npm package like the one you mentioned  and has it s own algorithm based on W3 spec  you could install and use the abab package rather than writing you own function that may or may not be accurate based on encoding   ---EDIT---  I started having weird issues today with encoding  not sure why it s started happening now  with package abab  It seems to encode correctly most of the time  but sometimes on front end it encodes incorrectly  Spent a long time trying to debug  but switched to package base-64 as recommended  and it worked straight away  Definitely seemed to be down to the base64 algorithm of abab

[node.js] Node.js throws "btoa is not defined" error

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