feat jest: setup jest environment with jsdom

[nowgnuesLeee]

Setting up Jest with jsdom environment and writing unit test code for Lottie Player

changes

• I created a folder named tests and wrote Jest-related code.
• Since we are using dynamic imports when importing the WASM module, we are using Node’s --experimental-vm-modules flag. ref.

var h = moduleArg, aa = "object" == typeof window, ba = "undefined" != typeof WorkerGlobalScope, ca = "object" == typeof process && process.versions?.node && "renderer" != process.type;
      if (ca) {
          const { createRequire: a } = await import('module');

• The nodePolyfills() plugin generates polyfills that are not usable in the Node environment, so I added a build:node script that can build without it.

if (ca) {
          const { createRequire: a } = await Promise.resolve().then(function () { return _polyfillNode_module; });
...
  var _polyfillNode_module = /*#__PURE__*/Object.freeze({
    __proto__: null
  });

test

• After running npm run build:node, please run npm run test.
• I got TypeError cannot read properties of undefined reading refcount when calling term() in the test environment

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Preview	Comments	Updated (UTC)
thorvg-perf-test	Ready	Preview	Comment	Sep 14, 2025 10:37am

[Copilot]

Pull Request Overview

This PR sets up Jest testing environment with jsdom for the Lottie Player project, enabling unit tests for the web component functionality. The setup includes mocking of browser APIs, WASM module handling, and comprehensive test coverage for the LottiePlayer component.

Key changes:

• Added Jest configuration with jsdom environment and Node.js ESM support
• Created comprehensive test mocks for browser APIs (IntersectionObserver, fetch, Canvas APIs)
• Implemented unit tests covering all major LottiePlayer methods and functionality
• Added Node.js-specific build configuration to handle WASM polyfills properly

Reviewed Changes

Copilot reviewed 5 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/setup.ts	Test environment setup with mocks for browser APIs and WASM module handling
tests/lottie-player.test.ts	Comprehensive unit tests for LottiePlayer component methods
tests/fixtures/base-template.html	HTML template for test DOM setup
rollup.config.js	Added conditional Node.js build configuration to exclude polyfills
package.json	Added Jest dependencies and test scripts with ESM support

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

The ts-jest dependency appears unused since the Jest configuration uses native Node.js ESM modules with --experimental-vm-modules flag instead of ts-jest transformation. Consider removing this dependency if it's not being used elsewhere.

Suggested change

"ts-jest": "^29.4.1",

[tinyjin]

Thank you. Please check comments

[tinyjin]

Don't use any. If it's only option, please add comment.

[tinyjin]

No need to change existing dependency.

[nowgnuesLeee]

Sorry, this is my mistake. I'll fix it.