Javascript – Decode URL Safe Base64 in JavaScript (browser side)

base64gmail-apijavascript

I am using Gmail's API to get emails from my account. The body of the message is delivered in a "URL safe base64" format. What is the best way to decode this for use? I have found some nodejs solutions, but no client side ones. window.atob does not work since it is URL safe.

Thanks for any help.

Best Solution

For posterity,

atob(data.replace(/_/g, '/').replace(/-/g, '+'))

As stated by the spec https://www.rfc-editor.org/rfc/rfc4648#section-5 however because this uses atob() it does not support unicode characters and thus requires a polyfill.

Related Solutions

Javascript – How to you encode a string to Base64 in JavaScript

You can use btoa() and atob() to convert to and from base64 encoding.

There appears to be some confusion in the comments regarding what these functions accept/return, so…

btoa() accepts a “string” where each character represents an 8-bit byte – if you 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 – that is, its value will be between 0 and 0xff. This does not mean it’s ASCII – presumably if you’re using this function at all, you expect to be working with binary data and not text.

See also:

How do I load binary image data using Javascript and XMLHttpRequest?

Most comments here are outdated. You can probably use both btoa() and atob(), unless you support really outdated browsers.

Check here:

Javascript – Encode URL in JavaScript

Check out the built-in function encodeURIComponent(str) and encodeURI(str).
In your case, this should work:

var myOtherUrl = 
       "http://example.com/index.html?url=" + encodeURIComponent(myUrl);

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