Modify vscode snippet by regex: TitleCase and SNAKE_CASE - visual-studio-code

Question

I have two questions for vscode snippets+regex;
I have a pathname like some-component and I need to generate an output like SomeComponent using vscode snippet.
I need to input sendData and return an string like const sendData = createMessage(SEND_DATA);
How can I do this using regex on vscode snippet?

Answer 1

"${TM_DIRECTORY/(.*)/${1:/pascalcase}/g}" you didn't really provide enough info on how you are getting your pathName, so this is just one possibility, perhaps RELATIVE_FILEPATH` works for you.
"$1 = createMessage(${1/(([^A-Z]+)(\\w*))/${2:/upcase}_${3:/upcase}/});"
split the input sendData into 2 capture groups $2 and $3. Upcase them both in the transform.
"sendData": {
"prefix": "cm",
"body": [
"${TM_DIRECTORY/(.*)/${1:/pascalcase}/}",
// simpler form if ONLY two "words" like "sendData"
"$1 = createMessage(${1/(([^A-Z]+)(\\w*))/${2:/upcase}_${3:/upcase}/});",
// for any number of words, like "sendDataTwoThreeFour" use this:
"$1 = createMessage(${1/([a-z]*)([A-Z][a-z]*)/${1:/upcase}${2:+_}${2:/upcase}/g});"
]
}
${1/([a-z]*)([A-Z][a-z]*)/${1:/upcase}${2:+_}${2:/upcase}/g} get the first word "send" into capture group 1 and the other words like "Data" or "Two", etc. into subsequent matches' capture group 2. [So the g flag at the end is very important.]
Upcase group1. Then if there is a group 2 ${2:+_} add _. Then upcase group2.
The only case this will not work on is send with nothing else. It still prints out the all the text just doesn't upcase send if it is by itself. There is probably a way to include that...
Edit: And here it is:
"$1 = createMessage(${1/([a-z]*)([A-Z][a-z]*)|([a-z]+)/${1:/upcase}${3:/upcase}${2:+_}${2:/upcase}/g});"
now a bare send will be put into group 3 and upcased. For the rest of the matches there will not be a group 3 so ${3:/upcase} returns nothing.