What is the current behavior?

Stencil lacks support for Jest 29

GitHub Issue Number: N/A

Note to Reviewers

This PR is meant to follow along with the steps for adding a new version of Jest, currently ready for review (#4952). I suggest reading that in tandem with this PR, each commit in this PR can be directly tied back to a step (there may be >1 commit per step) in that document.

This PR is a child of #4979. I plan on merging that first, then this one. I'll probably wait until both are approved to begin the merging/squashing/rebasing of the two branches

What is the new behavior?

Add support for Jest 29 to Stencil

Does this introduce a breaking change?

• Yes
• No

Testing

To test, I generated a dev build of the branch - @stencil/core@4.6.0-dev.1698239124.bd2fbc0

• Dev Release Workflow
• NPM Registry Entry

Component Starter Testing

I tested this on a Stencil Component Starter (manually).

I started by generating a new project with the dev build:

cd /tmp \
&& npm init stencil@latest component jest-test \
&& cd $_ \
&& npm i @stencil/core@4.6.0-dev.1698239124.bd2fbc0

Then installed each version of jest and tested them:

npm i jest@24 jest-cli@24 @types/jest@24 && npm t -- --no-cache && \
npm i jest@25 jest-cli@25 @types/jest@25 && npm t -- --no-cache && \
npm i jest@26 jest-cli@26 @types/jest@26 && npm t -- --no-cache && \
npm i jest@27 jest-cli@27 @types/jest@27 && npm t -- --no-cache && \
npm i jest@28 jest-cli@28 @types/jest@28 && npm t -- --no-cache && \
npm i jest@29 jest-cli@29 @types/jest@29 && npm t -- --no-cache

Ionic Framework

I tested this branch in the Ionic Framework as well.

Note: Node 18 is required to run tests here.

1. Pull the latest Ionic Framework code, check out main
2. cd core/ && npm i @stencil/core@4.6.0-dev.1698239124.bd2fbc0
3. npm i jest@29 @types/jest@29 jest-cli@29 @jest/core@29
4. npm run test.spec -- --no-cache
5. At this point, an error should appear
6. Apply the following patch:

diff --git a/core/src/components/datetime/test/data.spec.ts b/core/src/components/datetime/test/data.spec.ts
index 4484224402..0306d09f9c 100644
--- a/core/src/components/datetime/test/data.spec.ts
+++ b/core/src/components/datetime/test/data.spec.ts
@@ -482,7 +482,7 @@ describe('generateTime()', () => {
 
 describe('getToday', () => {
   beforeAll(() => {
-    jest.useFakeTimers('modern');
+    jest.useFakeTimers();

7. Rerun the tests, everything ought to pass now 👍

Other information

Docs PR: stenciljs/site#1257

Note to self When it's time to merge, please squash this, add the STENCIL- ticket number and the 'fixes' contents to the squashed commit