javascript - mongodb regex to find two words with exactly n or less words between them -

i want regex can query mongodb in following manner following results

1. a x y b
2. a x b
3. a b

in short want regex finds 2 words n words or less between them.

here go:

/start( \w+){0,n} end/ 

example

/start( \w+){0,1} end/ 

matches

start word word word end // no match start word word end      // no match start word end           // match start end                // match 

edit

you should use

/^start( \w+){0,n} end$/ 

this takes better advantage of mongodb's indexes querys , faster non-indexed fields.