It seems my question was not clear, so an exemple :
A folder contains few Gsheets.
each gSheet has 2 or more Bound Script projects
ex : Gsheet "Electronics" (id = "jkkljsdq;h..." ) has 2 Bound Script projects :
1) project name "prj1", id = "3jkqsmlkdsq"
2) project name "prj2", id = "1TFLUOI76...."
I know the Gsheet Id and I need to retrieve his 2 projects id.
Something like
getProjectId("jkkljsdq;h..." )
return ["3jkqsmlkdsq", "1TFLUOI76....")