Convert TypeScript sources to NodeNext ESM

[dibarbet]

Summary

• mark the package as ESM and convert first-party TypeScript away from CommonJS globals and module patterns
• upgrade TypeScript from 5.6.2 to 5.7.3 and enable rewriteRelativeImportExtensions while retaining module/moduleResolution: NodeNext
• write relative first-party imports with their actual .ts source extensions; TypeScript rewrites them to .js throughout out/, including all directly loaded VS Code integration entries
• preserve six intentional .mjs support imports, Jest’s required transformed-.js source mapper, runtime-correct CJS interop, existing output/copy behavior, and the bundle-level createRequire(import.meta.url) bridge
• remove the temporary bundle __filename/__dirname shim now that all first-party usages use import.meta.url

Validation

• npm run compileDev
• emitted-output audit: zero relative .ts imports and correct .js integration-runner imports
• raw Node import of all four emitted integration entry points
• npm run test:unit (11 suites, 514 tests, 350 snapshots)
• npm run packageDev and node --check dist/extension.mjs
• npm run test:integration:untrusted (1 test)
• npm run test:integration:csharp (21 suites, 73 passed, 3 skipped)
• OmniSharp unit project (37 suites, 401 tests)
• source audit: 1,449 relative .ts imports, six intentional .mjs imports, zero extensionless/.js/.cjs source imports, and no __filename/__dirname source or banner definitions

[Copilot]

Pull request overview

Converts the extension’s TypeScript codebase and build/test tooling to an ESM-first setup (NodeNext), replacing CommonJS globals/patterns with import.meta.url-based equivalents while preserving Jest, esbuild bundling, and VS Code integration entry points.

Changes:

• Switch TypeScript typechecking to module: Preserve / moduleResolution: Bundler with noEmit, and add dedicated tsconfig files for Jest (CJS) and integration entry point emission (NodeNext).
• Update tests/tooling to work in an ESM package (type: module), including Jest config split for integration vs unit runs and updated runners/import specifiers.
• Replace CommonJS-only patterns (__dirname, require, module.exports) with ESM-compatible equivalents across tasks, tests, and runtime code.

Show a summary per file

File	Description
wallaby.js	Convert Wallaby config to ESM export default.
tsconfig.json	Switch to ESM-preserving typecheck config (Preserve/Bundler, noEmit).
tsconfig.jest.json	Add CJS tsconfig override for Jest preset needing CommonJS.
tsconfig.integration.json	Add NodeNext-emitting config for VS Code integration test entry points.
test/vsCodeUnitFramework.ts	Ensure vscode virtual mock is set up for both Jest mock systems.
test/vsCodeFramework.ts	Add ESM-compatible unstable_mockModule for vscode virtual mock.
test/vsCodeEnvironment.ts	Export Jest environment class via ESM default export.
test/untrustedWorkspace/integrationTests/jest.config.mjs	Use the integration-oriented base Jest config.
test/untrustedWorkspace/integrationTests/index.ts	Use explicit .js specifier for compiled runner import edge.
test/runIntegrationTests.ts	Switch to default-imported Jest API for ESM runtime.
test/razor/razorTests/Microsoft.AspNetCore.Razor.VSCode.Grammar.Test/tests/infrastructure/tokenizedContentProvider.ts	Replace __dirname with import.meta.url-based pathing and adjust CJS interop imports.
test/razor/razorIntegrationTests/jest.config.mjs	Use the integration-oriented base Jest config.
test/razor/razorIntegrationTests/index.ts	Use explicit .js specifier for compiled runner import edge.
test/omnisharp/runFeatureTests.ts	Replace __dirname usage with import.meta.url-based directory resolution.
test/omnisharp/omnisharpUnitTests/testAssets/mockHttpsServer.ts	Use createRequire(import.meta.url) bridge for CJS-only dependency.
test/omnisharp/omnisharpUnitTests/packages/zipInstaller.test.ts	Update fs-extra import for ESM/CJS interop.
test/omnisharp/omnisharpUnitTests/packages/packageFilterer.test.ts	Convert fs mocking to unstable_mockModule + top-level await import(...).
test/omnisharp/omnisharpUnitTests/jest.config.mjs	Add unit test setup file for vscode mocking.
test/omnisharp/omnisharpUnitTests/blazorWebAssemblyDetection.test.ts	Update fs-extra import for ESM/CJS interop.
test/omnisharp/omnisharpIntegrationTests/launchConfiguration.integration.test.ts	Update fs-extra import for ESM/CJS interop.
test/omnisharp/omnisharpIntegrationTests/jest.config.mjs	Use the integration-oriented base Jest config.
test/omnisharp/omnisharpIntegrationTests/index.ts	Use explicit .js specifier for compiled runner import edge.
test/lsptoolshost/unitTests/roslynLanguageClient.test.ts	Convert mocks/imports to ESM-safe unstable_mockModule + dynamic imports.
test/lsptoolshost/unitTests/migrateOptions.test.ts	Convert fs mocking to unstable_mockModule + top-level await import(...).
test/lsptoolshost/unitTests/jest.config.mjs	Add unit test setup file for vscode mocking.
test/lsptoolshost/integrationTests/testAssets/testAssets.ts	Update fs-extra import for ESM/CJS interop.
test/lsptoolshost/integrationTests/jest.config.mjs	Use the integration-oriented base Jest config.
test/lsptoolshost/integrationTests/index.ts	Use explicit .js specifier for compiled runner import edge.
test/lsptoolshost/artifactTests/vsix.test.ts	Update fs-extra and glob imports for ESM/CJS interop.
test/createTmpAsset.ts	Avoid named import from fs-extra in ESM; use namespace/default import.
tasks/tests/testHelpers.ts	Switch to default-imported Jest API for ESM runtime.
tasks/projectPaths.ts	Replace __dirname usage with import.meta.url-based root resolution.
tasks/packaging/offlinePackagingTasks.ts	Update fs-extra import for ESM/CJS interop.
tasks/compilation/copyEsmSupportFiles.ts	Add build step to copy .mjs Jest support file into out/test.
src/shared/workspaceConfigurationProvider.ts	Update fs-extra import for ESM/CJS interop.
src/shared/utils.ts	Update fs-extra import for ESM/CJS interop.
src/shared/telemetryReporter.ts	Add telemetry reporter interface that includes telemetryLevel.
src/shared/projectConfiguration.ts	Adjust node-machine-id import shape for ESM/CJS interop.
src/shared/processPicker.ts	Update fs-extra import for ESM/CJS interop.
src/shared/platform.ts	Replace __dirname usage with import.meta.url-based directory resolution.
src/shared/dotnetConfigurationProvider.ts	Update fs-extra import for ESM/CJS interop.
src/shared/assets.ts	Update fs-extra import for ESM/CJS interop.
src/razor/src/blazorDebug/blazorDebugConfigurationProvider.ts	Replace require('path') pattern and adjust servicehub imports for ESM.
src/packageManager/zipInstaller.ts	Avoid named import from fs-extra in ESM; use namespace/default import.
src/packageManager/downloadAndInstallPackages.ts	Avoid named import from fs-extra in ESM; use namespace/default import.
src/omnisharp/features/workspaceSymbolProvider.ts	Formatting-only rewrite consistent with ESM conversion.
src/omnisharp/features/definitionMetadataDocumentProvider.ts	Formatting-only rewrite consistent with ESM conversion.
src/omnisharp/engines/lspEngine.ts	Refactor feature disabling to use request/notification method IDs (ESM-friendly imports).
src/main.ts	Adjust extension-telemetry import for CJS interop under ESM.
src/lsptoolshost/server/roslynLanguageServer.ts	Accept telemetry reporter interface and expose protocol converter for workspace edits.
src/lsptoolshost/extensions/builtInComponents.ts	Replace __dirname usage with import.meta.url-based directory resolution.
src/lsptoolshost/diagnostics/nestedCodeAction.ts	Use shared protocol converter for workspace edits (and contains a typo to fix).
src/lsptoolshost/diagnostics/fixAllCodeAction.ts	Use shared protocol converter for workspace edits.
src/lsptoolshost/commands.ts	Decouple from concrete telemetry reporter type via local interface.
src/lsptoolshost/activate.ts	Replace __dirname usage and switch to telemetry reporter interface type.
src/activateRoslyn.ts	Switch telemetry reporter parameter to interface with telemetry level.
src/activateOmniSharp.ts	Switch telemetry reporter parameter to interface type.
package.json	Mark package as ESM and update compile/test scripts for ESM + Jest VM modules.
eslint.config.mjs	Expand ignore list to include .vscode-test/**.
esbuild.mjs	Remove temporary bundled __filename/__dirname shims from banner.
baseJestConfig.mjs	Split base Jest config for unit (ESM) vs integration (CJS) environments.
.vscode/launch.json	Point integration test launch configs at explicit compiled index.js entry points.
mocks/vscode.ts	Convert vscode manual mock to ESM exports shape.

Copilot's findings

Suppressed comments (1)

src/lsptoolshost/diagnostics/nestedCodeAction.ts:77

• Error message has a typo (“am edit”), and it’s inconsistent with the earlier log line that says “an edit”. This can make logs/telemetry harder to search and understand.

                            const componentName = '[roslyn.client.nestedCodeAction]';
                            const errorMessage = 'Failed to make am edit for completion.';
                            outputChannel.show();

• Files reviewed: 60/63 changed files
• Comments generated: 0

[Copilot]

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[dibarbet]

Superseded by #9632 on dev/esm-nodenext-conversion so the updated branch trigger runs CI. The replacement PR is part of stack #9634.