Fix type definitions for custom helpers with ESM default exports

lib/command/definitions.js

@@ -239,8 +239,13 @@ function getImportString(testsPath, targetFolderPath, pathsToType, pathsToValue)
   }
 
   for (const name in pathsToValue) {
-    const relativePath = getPath(pathsToValue[name], targetFolderPath, testsPath)
-    importStrings.push(`type ${name} = import('${relativePath}');`)
+    const originalPath = pathsToValue[name]
+    const relativePath = getPath(originalPath, targetFolderPath, testsPath)
+    if (originalPath.endsWith('.js') || originalPath.endsWith('.ts')) {
+      importStrings.push(`type ${name} = InstanceType<typeof import('${relativePath}').default>;`)
+    } else {
+      importStrings.push(`type ${name} = import('${relativePath}');`)
+    }
   }
 
   return importStrings

test/data/sandbox/configs/custom-helper-esm/My_test.ts

@@ -0,0 +1,7 @@
+Feature("My");
+
+const {I} = inject();
+
+Scenario("test something", () => {
+    I.openPage("http://codecept.io");
+});

test/data/sandbox/configs/custom-helper-esm/codecept-ts.conf.js

@@ -0,0 +1,14 @@
+export const config = {
+  tests: './*_test.js',
+  output: './output',
+  helpers: {
+    FileSystem: {},
+    MyHelperTs: {
+      require: './myhelper_ts.ts',
+    },
+  },
+  include: {},
+  bootstrap: false,
+  mocha: {},
+  name: 'custom-helper-esm-ts',
+};

test/data/sandbox/configs/custom-helper-esm/codecept.conf.js

@@ -0,0 +1,14 @@
+export const config = {
+  tests: './*_test.js',
+  output: './output',
+  helpers: {
+    FileSystem: {},
+    MyHelper: {
+      require: './myhelper_helper.js',
+    },
+  },
+  include: {},
+  bootstrap: false,
+  mocha: {},
+  name: 'custom-helper-esm',
+};

test/data/sandbox/configs/custom-helper-esm/myhelper_helper.js

@@ -0,0 +1,9 @@
+import Helper from '../../../../../lib/helper.js';
+
+class MyHelper extends Helper {
+  openPage(url) {
+    return this.helpers.FileSystem.amInPath(url);
+  }
+}
+
+export default MyHelper;

test/data/sandbox/configs/custom-helper-esm/myhelper_ts.ts

@@ -0,0 +1,9 @@
+import Helper from '../../../../../lib/helper.js';
+
+class MyHelperTs extends Helper {
+  openPageTs(url: string): Promise<void> {
+    return this.helpers.FileSystem.amInPath(url);
+  }
+}
+
+export default MyHelperTs;

test/runner/definitions_test.js

@@ -261,6 +261,28 @@ describe('Definitions', function () {
       done()
     })
   })
+
+  it('def should create definition file with custom helper using ESM default export', done => {
+    const customHelperDir = `${codecept_dir}/../custom-helper-esm`
+    exec(`${runner} def --config ${customHelperDir}/codecept.conf.js`, (err, stdout) => {
+      stdout.should.include('Definitions were generated in steps.d.ts')
+      const types = typesFrom(`${customHelperDir}/steps.d.ts`)
+      types.should.be.valid
+
+      const definitionFile = types.getSourceFileOrThrow(`${customHelperDir}/steps.d.ts`)
+      const fileContent = definitionFile.getFullText()
+      fileContent.should.include("type MyHelper = InstanceType<typeof import('./myhelper_helper.js').default>;")
+
+      const extend = getExtends(definitionFile.getModule('CodeceptJS').getInterfaceOrThrow('I'))
+      const hasOpenPageMethod = extend.some(ext => 
+        ext.methods && ext.methods.some(m => m.name === 'openPage')
+      )
+      hasOpenPageMethod.should.be.true
+
+      assert(!err)
+      done()
+    })
+  })
 })
 
 /**