validate paths without baseUrl requires configFilePath

RealColdFry · RealColdFry · commit 1623c04990c2 · 2026-04-02T23:10:43.000+01:00
diff --git a/src/CompilerOptions.ts b/src/CompilerOptions.ts
@@ -99,7 +99,9 @@ export function validateOptions(options: CompilerOptions): ts.Diagnostic[] {
         diagnostics.push(diagnosticFactories.unsupportedJsxEmit());
     }
 
-    // paths without baseUrl is now supported (TS 6.0+ resolves paths relative to tsconfig location)
+    if (options.paths && Object.keys(options.paths).length > 0 && !options.baseUrl && !options.configFilePath) {
+        diagnostics.push(diagnosticFactories.pathsWithoutBaseDirectory());
+    }
 
     return diagnostics;
 }
diff --git a/src/transpilation/diagnostics.ts b/src/transpilation/diagnostics.ts
@@ -55,3 +55,8 @@ export const cannotBundleLibrary = createDiagnosticFactory(
 );
 
 export const unsupportedJsxEmit = createDiagnosticFactory(() => 'JSX is only supported with "react" jsx option.');
+
+export const pathsWithoutBaseDirectory = createDiagnosticFactory(
+    () =>
+        "When using 'paths' without 'baseUrl', a tsconfig.json must be present so paths can be resolved relative to it."
+);

Original file line number	Diff line number	Diff line change
`@@ -99,7 +99,9 @@ export function validateOptions(options: CompilerOptions): ts.Diagnostic[] {`
`99`	`99`	`diagnostics.push(diagnosticFactories.unsupportedJsxEmit());`
`100`	`100`	`}`
`101`	`101`
`102`		`- // paths without baseUrl is now supported (TS 6.0+ resolves paths relative to tsconfig location)`
	`102`	`+ if (options.paths && Object.keys(options.paths).length > 0 && !options.baseUrl && !options.configFilePath) {`
	`103`	`+ diagnostics.push(diagnosticFactories.pathsWithoutBaseDirectory());`
	`104`	`+ }`
`103`	`105`
`104`	`106`	`return diagnostics;`
`105`	`107`	`}`