isBase64 padding support

[antonio-ivanovski]

Describe the bug

Sometimes when base64 strings has the padding removed for either legacy or bandwidth purposes. In those cases, the padding check needs to be ignored or manually the padding to be added.

Either this should be the default behavior or config option should be added.

Examples

// const base64 = Buffer.from([1,2,3,4]).toString('base64');
const base64 = 'AQIDBA';
const result = isBase64(base64); // false, should be true

[jamro]

I think this is expected behaviour. While RFC 4648 permits Base64 without padding, it states that padding should be used unless all parties involved agree to omit it.

Implementations MUST include appropriate pad characters at the end of
encoded data unless the specification referring to this document
explicitly states otherwise.

isBase64 has the flag urlSafe, which could be used to handle legacy use cases.

const result = validator.isBase64(base64, {urlSafe:  true}); // true

[antonio-ivanovski]

isBase64 has the flag urlSafe, which could be used to handle legacy use cases.

The base64url is different encoding to the normal base64, other encoding dictionary is used.w

I think this is expected behaviour. While RFC 4648 permits Base64 without padding, it states that padding should be used unless all parties involved agree to omit it.

Makes sense for the current behaviour to be the default one, considering it is part of the spec. But it seems reasonable to me there to be an option to support such cases where the parties agree to such behaviour.

[jamro]

makes sense @antonio-ivanovski

[WikiRik]

I think we've added this with #2491