Decodes standard, padded base64 back to bytes — strictly.
"Strictly" means the decoder is the exact inverse of encodeBase64 and
accepts nothing else: no whitespace or line breaks, no URL-safe -_, no
missing padding, and no non-zero unused bits in a padded group ("Zg=="
is accepted, "Zh==" is not — both would decode to the same byte, and a
format that admits two spellings of one buffer cannot be compared byte for
byte). Every rejection is a TypeError naming the offence.
Decodes standard, padded base64 back to bytes — strictly.
"Strictly" means the decoder is the exact inverse of encodeBase64 and accepts nothing else: no whitespace or line breaks, no URL-safe
-_, no missing padding, and no non-zero unused bits in a padded group ("Zg=="is accepted,"Zh=="is not — both would decode to the same byte, and a format that admits two spellings of one buffer cannot be compared byte for byte). Every rejection is a TypeError naming the offence.