feat(test runner): support jsconfig.json's baseUrl+paths (#19219)

Fixes #19129.

packages/playwright-test/src/third_party/tsconfig-loader.ts

@@ -102,9 +102,13 @@ export function walkForTsConfig(
   directory: string,
   existsSync: (path: string) => boolean = fs.existsSync
 ): string | undefined {
-  const configPath = path.join(directory, "./tsconfig.json");
-  if (existsSync(configPath)) {
-    return configPath;
+  const tsconfigPath = path.join(directory, "./tsconfig.json");
+  if (existsSync(tsconfigPath)) {
+    return tsconfigPath;
+  }
+  const jsconfigPath = path.join(directory, "./jsconfig.json");
+  if (existsSync(jsconfigPath)) {
+    return jsconfigPath;
   }
 
   const parentDirectory = path.join(directory, "../");
@@ -129,7 +133,7 @@ function loadTsconfig(
 
   const configString = readFileSync(configFilePath);
   const cleanedJson = StripBom(configString);
-  const config: Tsconfig = json5.parse(cleanedJson);
+  let config: Tsconfig = json5.parse(cleanedJson);
   let extendedConfig = config.extends;
 
   if (extendedConfig) {
@@ -166,7 +170,7 @@ function loadTsconfig(
       );
     }
 
-    return {
+    config = {
       ...base,
       ...config,
       compilerOptions: {
@@ -175,6 +179,12 @@ function loadTsconfig(
       },
     };
   }
+
+  if (path.basename(configFilePath) === 'jsconfig.json' && config.compilerOptions?.allowJs === undefined) {
+    config.compilerOptions = config.compilerOptions || {};
+    config.compilerOptions.allowJs = true;
+  }
+
   return config;
 }
 

tests/playwright-test/resolver.spec.ts

@@ -398,3 +398,37 @@ test('should not respect path resolver for JS files w/o allowJS', async ({ runIn
   expect(stripAnsi(result.output)).toContain('Cannot find module \'util/b\'');
   expect(result.exitCode).toBe(1);
 });
+
+test('should respect path resolver for JS and TS files from jsconfig.json', async ({ runInlineTest }) => {
+  const result = await runInlineTest({
+    'playwright.config.ts': `export default { projects: [{name: 'foo'}], };`,
+    'jsconfig.json': `{
+      "compilerOptions": {
+        "baseUrl": ".",
+        "paths": {
+          "util/*": ["./foo/bar/util/*"],
+        },
+      },
+    }`,
+    'a.test.js': `
+      const { foo } = require('util/b');
+      const { test } = pwt;
+      test('test', ({}, testInfo) => {
+        expect(testInfo.project.name).toBe(foo);
+      });
+    `,
+    'b.test.ts': `
+      import { foo } from 'util/b';
+      const { test } = pwt;
+      test('test', ({}, testInfo) => {
+        expect(testInfo.project.name).toBe(foo);
+      });
+    `,
+    'foo/bar/util/b.ts': `
+      module.exports = { foo: 'foo' };
+    `,
+  });
+
+  expect(result.passed).toBe(2);
+  expect(result.exitCode).toBe(0);
+});