fix: several regressions in TS compiler (#6177)

This commit fixes several regressions in TS compiler:

* double compilation of same module during same process run

* compilation of JavaScript entry point with non-JS imports

* unexpected skip of emit during compilation

Additional checks were added to ensure "allowJs" setting is 
used in TS compiler if JavaScript has non-JS dependencies.

1 files changed, 22 insertions, 1 deletions

diff --git a/cli/js/compiler.ts b/cli/js/compiler.ts
index 06117413a..abe145da2 100644
--- a/cli/js/compiler.ts
+++ b/cli/js/compiler.ts
@@ -1049,6 +1049,7 @@ interface SourceFileMapEntry {
 
 interface CompilerRequestCompile {
   type: CompilerRequestType.Compile;
+  allowJs: boolean;
   target: CompilerHostTarget;
   rootNames: string[];
   configPath?: string;
@@ -1099,6 +1100,7 @@ interface RuntimeBundleResult {
 
 function compile(request: CompilerRequestCompile): CompileResult {
   const {
+    allowJs,
     bundle,
     config,
     configPath,
@@ -1138,6 +1140,10 @@ function compile(request: CompilerRequestCompile): CompileResult {
   }));
   let diagnostics: readonly ts.Diagnostic[] = [];
 
+  if (!bundle) {
+    host.mergeOptions({ allowJs });
+  }
+
   // if there is a configuration supplied, we need to parse that
   if (config && config.length && configPath) {
     const configResult = host.configure(cwd, configPath, config);
@@ -1167,7 +1173,22 @@ function compile(request: CompilerRequestCompile): CompileResult {
         setRootExports(program, rootNames[0]);
       }
       const emitResult = program.emit();
-      assert(emitResult.emitSkipped === false, "Unexpected skip of the emit.");
+      // If `checkJs` is off we still might be compiling entry point JavaScript file
+      // (if it has `.ts` imports), but it won't be emitted. In that case we skip
+      // assertion.
+      if (!bundle) {
+        if (options.checkJs) {
+          assert(
+            emitResult.emitSkipped === false,
+            "Unexpected skip of the emit."
+          );
+        }
+      } else {
+        assert(
+          emitResult.emitSkipped === false,
+          "Unexpected skip of the emit."
+        );
+      }
       // emitResult.diagnostics is `readonly` in TS3.5+ and can't be assigned
       // without casting.
       diagnostics = emitResult.diagnostics;