Irregular

0.6

RegEx/JSON/PropertyName.regex.txt

                                # A property within a JSON string

(?<=             # After:

[\{\,]           # A bracket or comma

)

\s{0,}           # Optional Whitespace

(?<Quoted>["'])? # There's an optional opening quote

(?<Name>         # Capture the Name, which is:

.+?              # Anything until...

)

(?=              

    (?(Quoted)   # If quoted

        ((?<!\\)\k<Quoted>) # the closing quote

        |

        ([\s:])  # otherwise, whitespace or a colon

    )

)

(?:              # Match but don't store:

    (?(Quoted)(\k<Quoted>))

\s{0,}     # a double-quote, optional whitespace:

)

(?=\:)      # Look ahead to see that we're followed by a :, but don't include it in the match.