fix: mis-detecting imports on JavaScript when there is no checkJs (#4040)

This PR fixes an issue where we recursively analysed imports on plain JS files
in the compiler irrespective of "checkJs" being true. This caused problems
where when analysing the imports of those files, we would mistake some
import like structures (AMD/CommonJS) as dependencies and try to resolve
the "modules" even though the compiler would not actually look at those files.

1 files changed, 9 insertions, 7 deletions

diff --git a/cli/js/compiler.ts b/cli/js/compiler.ts
index 4ca2887c6..3db0e2f52 100644
--- a/cli/js/compiler.ts
+++ b/cli/js/compiler.ts
@@ -105,13 +105,6 @@ async function tsCompilerOnMessage({
         type: CompilerRequestType[request.type]
       });
 
-      // This will recursively analyse all the code for other imports,
-      // requesting those from the privileged side, populating the in memory
-      // cache which will be used by the host, before resolving.
-      const resolvedRootModules = await processImports(
-        rootNames.map(rootName => [rootName, rootName])
-      );
-
       // When a programme is emitted, TypeScript will call `writeFile` with
       // each file that needs to be emitted.  The Deno compiler host delegates
       // this, to make it easier to perform the right actions, which vary
@@ -141,6 +134,15 @@ async function tsCompilerOnMessage({
         diagnostics = processConfigureResponse(configResult, configPath);
       }
 
+      // This will recursively analyse all the code for other imports,
+      // requesting those from the privileged side, populating the in memory
+      // cache which will be used by the host, before resolving.
+      const resolvedRootModules = await processImports(
+        rootNames.map(rootName => [rootName, rootName]),
+        undefined,
+        host.getCompilationSettings().checkJs
+      );
+
       let emitSkipped = true;
       // if there was a configuration and no diagnostics with it, we will continue
       // to generate the program and possibly emit it.