Determine if string is in base64 using JavaScript

Question

I\'m using the window.atob(\'string\') function to decode a string from base64 to a string. Now I wonder, is there any way to check that \'string\' is actually

Answer 1

As there are mostly two possibilities posted here (regex vs try catch) I did compare the performance of both: https://jsperf.com/base64-check/

Regex solution seems to be much faster and clear winner. Not sure if the regex catches all cases but for my tests it worked perfectly.

Thanks to @Philzen for the regex!

p.s.

In case someone is interested in finding the fastest way to safely decode a base64 string (that's how I came here): https://jsperf.com/base64-decoding-check