javascript - Need help parsing markdown, remove italic (*) but not bold(**) -

i trying replicate wmd markdown editor. tried modify wmd instead of reinventing wheel code not readable me ...

so trying allow removing of italics "*" not bold "**"

so, italics below should removed

this *is a* test ***is a*** test 

but below should untouched

this **is a** test 

i guess should use regexp how? how match * if "alone" or followed 2 or more *s

this hard solve straight regexp, handling edge cases asterisks @ beginning or end of string. mixing regexp magic replace magic gets job done though...

function removeitalics(str) {     var re = /\*+/g;     return str.replace(re, function(match, index) { return match.length === 2 ? '**' : ''; }); }  alert(removeitalics("this *is a* test"));     // test alert(removeitalics("this **is a** test"));   // **is a** test alert(removeitalics("this ***is a*** test")); // test 

we're matching runs of 1 or more asterisks. matches greedy. longest run of asterisks matched. if length of match 2, put asterisks back, otherwise strip them.

working example here: http://jsfiddle.net/qknam/

update: if want keep bold if have 2 or more asterisks, change match.length logic this...

function removeitalics(str) {     var re = /\*+/g;     return str.replace(re, function(match, index) { return match.length === 1 ? '' : '**'; }); }  alert(removeitalics("this *is a* test"));     // test alert(removeitalics("this **is a** test"));   // **is a** test alert(removeitalics("this ***is a*** test")); // **is a** test 

updated jsfiddle: http://jsfiddle.net/qknam/3/