Regex split on upper case and first digit

Question

I need to split the string "thisIs12MyString" to an array looking like [ "this", "Is", "12", "My", "String" ]

I've got so far as to "thisIs12MyString".split(/(?=[A-Z0-9])/) but it splits on each digit and gives the array [ "this", "Is", "1", "2", "My", "String" ]

So in words I need to split the string on upper case letter and digits that does not have an another digit in front of it.

Answer 1

Are you looking for this?

"thisIs12MyString".match(/[A-Z]?[a-z]+|[0-9]+/g)

returns

["this", "Is", "12", "My", "String"]

Answer 2

As I said in my comment, my approach would be to insert a special character before each sequence of digits first, as a marker:

"thisIs12MyString".replace(/\d+/g, '~$&').split(/(?=[A-Z])|~/)

where ~ could be any other character, preferably a non-printable one (e.g. a control character), as it is unlikely to appear "naturally" in a string.

In that case, you could even insert the marker before each capital letter as well, and omit the lookahead, making the split very easy:

"thisIs12MyString".replace(/\d+|[A-Z]/g, '~$&').split('~')

It might or might not perform better.