Validate dates in the format of 20201231 with leap year check on the 29th of February

Sourced from https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/488478/Bulk_Data_Transfer_-_additional_validation_valid_from_12_November_2015.pdf and modified to allows spaces to be optional

Validate dates in the formats of 1Feb20/01Feb20/29FEB20 with the 29th of February invalid on non-leap years.

This will allow for valid string parsing via a regex in popular interpreted languages like Lua, Python and Ruby.

Add single quotes to unquoted parts of a valid JS hash so it can be parsed with JSON decoders. Tries to keep boolean and numeric values unquoted Note: It will not handle certain edge-cases You might need to clear the trailing commas

A regex I use to Tokenize Hashtags in common textflow

15 digits for integer real number: 18 digits for before-dot part (*what it's called?)