In previous versions of angular, hashed file names looked like this: runtime.59772ce71fd8c096.js polyfills.efe34593e33fb8e1.js scripts.109c3e02aa410456.js main.3645a30dcf6ebeb0.js There was a name followed by a dot, then 16 characters of hexadecimal encoding of hash, then the extension. Now they look like this: styles-GCSEUS35.css chunk-NLN56U2H.js polyfills-UCPGG4LZ.js main-UFPD5ECZ.js They are composed by a name followed by an hyphen, then the hash encoded in 8 characters, ending with the extension. I need to know what characters are allowed to be part of the encoded hash. The reason is that my server returns cache-for-long-time headers when it detects that the file is an Angular hashed file. And now I don't know how to figure out if it is or it is not. Continue reading...