refactor: cleanup compiler pipeline (#2686)

* remove fetch_source_file_and_maybe_compile_async and 
  replace it with State.fetch_compiled_module

* remove SourceFile.js_source()

* introduce CompiledModule which is basically the same as
  deno::SourceInfo and represents arbitrary file that has been 
  compiled to JS module

* introduce //cli/compilers module containing all compilers

* introduce JsCompiler which is a no-op compiler
  - output is the same as input, no compilation takes place
  - it is used for MediaType::JavaScript and MediaType::Unknown

* introduce JsonCompiler that wraps JSON in default export

* support JS-to-JS compilation using checkJs

1 files changed, 0 insertions, 21 deletions

diff --git a/cli/file_fetcher.rs b/cli/file_fetcher.rs
index 656ecfff0..79d6ede00 100644
--- a/cli/file_fetcher.rs
+++ b/cli/file_fetcher.rs
@@ -39,27 +39,6 @@ pub struct SourceFile {
   pub source_code: Vec<u8>,
 }
 
-impl SourceFile {
-  // TODO(bartlomieju): this method should be implemented on new `CompiledSourceFile`
-  // trait and should be handled by "compiler pipeline"
-  pub fn js_source(&self) -> String {
-    if self.media_type == msg::MediaType::TypeScript {
-      panic!("TypeScript module has no JS source, did you forget to run it through compiler?");
-    }
-
-    // TODO: this should be done by compiler and JS module should be returned
-    if self.media_type == msg::MediaType::Json {
-      return format!(
-        "export default {};",
-        str::from_utf8(&self.source_code).unwrap()
-      );
-    }
-
-    // it's either JS or Unknown media type
-    str::from_utf8(&self.source_code).unwrap().to_string()
-  }
-}
-
 pub type SourceFileFuture =
   dyn Future<Item = SourceFile, Error = ErrBox> + Send;