Split string data into array based on new line and then double digit number

Question

What I'm looking to do is split data from string into an array.

Here's the general idea of the text format...

xxxxx denotes any mix of alpha-numeric-whitespace data.

xxxxx
 1 xxxxxxxxxx
 2 xxxxxxxxxx
xxxxxxxxx
xxxxxxxxx
xxxxxxxx
 3 xxxxxxxxxx
 4 xxxxxxxxxx
xxxxxxxxxx
 5 xxxxxxxxxx

(When numbers get into the double digits, the ten's place goes into the blank position in-front of the number)

Now what I want to do is have an array of 5 elements (in this case), which stores the number and all data that trails (including the new lines). In the past this was not a big deal and I could use string.split("\n") , but now I need to delimit based on some sort of regex like /\n [0-9]{1,2}/ so I'm looking for a quick and easy way to do this (as split() doesn't support regex).

I want the array to be like

array[1] = " 1 xxxxxxxxxx"
array[2] = " 2 xxxxxxxxxxx\nxxxxxxxxxx\nxxxxxxxxxx"
array[3] = " 3 xxxxxxxxxx"
...etc

Answer 1

split() does support regexes. Try this:

text.split(/\n(?=[1-9 ][0-9] )/)

Answer 2

You can use lookahead and split on (?= [1-9] |[1-9][0-9] ), perhaps anchored at the beginning of a line, but there may be issues with ambiguities in the xxxx part. This also doesn't ensure that the numbering is sequential.

Example

var text =
  "preface\n" +
  " 1 intro\n" +
  " 2 body\n" +
  "more body\n" +
  " 3 stuff\n" +
  "more stuff\n" +
  "even 4 stuff\n" +
  "10 conclusion\n" +
  "13 appendix\n";

print(text.split(/^(?= [1-9] |[1-9][0-9] )/m));

The output is (as seen on ideone.com):

preface
, 1 intro
, 2 body
more body
, 3 stuff
more stuff
even 4 stuff
,10 conclusion
,13 appendix