Is it possible to write a parser that only processes javascript import statements and ignores the rest?

[cristiano-belloni]

Hi,
I need to parse all the import / require statements from javascript and typescript files, in order to extract all the dependencies imported from the source of a package. This involves translating code to javascript / esm and using a pre-existant javascript parser to extract the imports, which is not too computationally efficient.
I'm new to the lexer / parser world and I have a question: would it be possible to write a parser that is able to parse javascript / typescript import or require statements (I don't need the assignment part) and simply ignore the rest? Or do I need to specify the whole js / ts grammar anyway?

[bd82]

It would be possible in general to extract specific statements, I have done so in another language (ABAP).
Doing so in JavaScript / TypeScript however may be hard due to:

• ECMAScript cannot (easily) be split into tokens separately from parsing

  • https://stackoverflow.com/questions/5519596/when-parsing-javascript-what-determines-the-meaning-of-a-slash
  • So Chevrotain may not be the best tool for the job.

• You would need to identify and "throw away" all other kind of statements / expressions and that is tricky
  because there is no clear indication where a statement ends, (e.g optional semi colon / multi line statements).

[msujew]

In addition to @bd82 said, something like acorn will definitely be better suited for this than some kind of partial Chevrotain based JavaScript parser.