Migrate client-metrics-web to ESM

.circleci/config.yml

@@ -14,7 +14,7 @@ references:
       - image: cimg/node:<< parameters.node-version >>
     parameters:
       node-version:
-        default: "22.13" # We default to the highest active LTS
+        default: "24.12" # We default to the highest active LTS
         type: string
 
   workspace_root: &workspace_root ~/project
@@ -76,7 +76,7 @@ jobs:
       - checkout
       - *restore_cache
       - node/install-npm:
-          version: '10.2.5'
+          version: '11.7.0'
       - run:
           name: Install project dependencies
           command: npm install
@@ -151,29 +151,29 @@ workflows:
           name: build-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - test:
           requires:
             - build-v<< matrix.node-version >>
           name: test-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - lint:
           requires:
             - build-v<< matrix.node-version >>
           name: lint-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - release-please:
           filters:
             <<: *filters_only_main
           requires:
             # We release on the highest active LTS version of
             # Node.js that we support
-            - test-v22.13
-            - lint-v22.13
+            - test-v24.12
+            - lint-v24.12
 
   build-test-publish:
     jobs:
@@ -183,7 +183,7 @@ workflows:
           name: build-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - test:
           filters:
             <<: *filters_release_build
@@ -192,7 +192,7 @@ workflows:
           name: test-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - lint:
           filters:
             <<: *filters_release_build
@@ -201,16 +201,16 @@ workflows:
           name: lint-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - publish:
           context: npm-publish-token
           filters:
             <<: *filters_release_build
           requires:
             # We release on the highest active LTS version of
             # Node.js that we support
-            - lint-v22.13
-            - test-v22.13
+            - lint-v24.12
+            - test-v24.12
 
   build-test-prepublish:
     jobs:
@@ -220,7 +220,7 @@ workflows:
           name: build-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - test:
           filters:
             <<: *filters_prerelease_build
@@ -229,7 +229,7 @@ workflows:
           name: test-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - lint:
           filters:
             <<: *filters_prerelease_build
@@ -238,16 +238,16 @@ workflows:
           name: lint-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - prepublish:
           context: npm-publish-token
           filters:
             <<: *filters_prerelease_build
           requires:
             # We release on the highest active LTS version of
             # Node.js that we support
-            - lint-v22.13
-            - test-v22.13
+            - lint-v24.12
+            - test-v24.12
 
   nightly:
     triggers:
@@ -261,12 +261,12 @@ workflows:
           name: build-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]
       - test:
           requires:
             - build-v<< matrix.node-version >>
           context: next-nightly-build
           name: test-v<< matrix.node-version >>
           matrix:
             parameters:
-              node-version: [ "24.0", "22.13", "20.18" ]
+              node-version: [ "24.12", "22.21" ]

.github/workflows/commitlint.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v3
         with:
-          node-version: 20
+          node-version: 24
 
       - name: Install dependencies
         run: npm install

biome.json

@@ -23,17 +23,7 @@
 			"quoteStyle": "single",
 			"jsxQuoteStyle": "double",
 			"trailingCommas": "none"
-		},
-		"globals": [
-			"afterAll",
-			"afterEach",
-			"beforeAll",
-			"beforeEach",
-			"describe",
-			"expect",
-			"it",
-			"jest"
-		]
+		}
 	},
 	"json": {
 		"formatter": {

docs/contributing.md

@@ -183,7 +183,7 @@ As with Biome, we check types in pull requests and errors will block merging, so
 
 ### Unit tests
 
-We run unit tests with [Jest](https://jestjs.io/) across most of our packages and aim for [100% coverage](#coverage). Tests are written within each package (e.g. `packages/example/test/example.spec.js`). You can run the tests with the following:
+We run unit tests with [the Node test runner](https://nodejs.org/api/test.html) across most of our packages and aim for [100% coverage](#coverage). Tests are written within each package (e.g. `packages/example/test/example.spec.js`). You can run the tests with the following:
 
 ```
 npm run test
@@ -195,14 +195,21 @@ To run the tests for a single package, use:
 npm run test -w packages/<name>
 ```
 
+You can also run unit and end-to-end tests specifically. You might want to do this to get a quick sense check on your code, because unit tests generally run a lot faster. To do this, replace the `test` command above with either `test:unit` or `test:end-to-end`, e.g.
+
+```
+npm run test:unit
+npm run test:end-to-end -w packages/<name>
+```
+
 Tests are also run on pull requests and failing tests will block merging, so it's useful to check before opening a PR.
 
 #### Coverage
 
 We intentionally fail the unit tests if coverage drops below 100%. This library is meant to help our applications be more reliable and so it's important that we cover as many edge cases as possible. If you have a valid reason for some code not to be covered, e.g. an empty function as a default parameter, then [use code comments to disable coverage](https://github.com/gotwarlost/istanbul/blob/master/ignoring-code-for-coverage.md) for that line or block:
 
 ```js
-/* istanbul ignore next */
+/* node:coverage ignore next */
 function example() { console.log('this is not covered'); }
 ```
 

docs/design.md

@@ -37,7 +37,7 @@ If we wanted to support ES Modules (which _is_ the future direction I think we'l
 
   2. We write our code in ES Modules and publish them as ES Modules with no cross-compilation. This makes them incompatible with a large number of our apps (many of them use CommonJS exclusively) and would tie adopting Reliability Kit to an unrelated migration step
 
-A note that for now there is a small downside to sticking with CommonJS. It will continue to work [for the forseeable future](https://github.com/nodejs/node/issues/33954) in Node.js itself, but more modules on npm are switching to native ESM which is not very compatible with CommonJS. We may find ourselves forced to reconsider at some point if any of our key dependencies (e.g. Express or Jest) migrate to ESM-only and drop support for their old CommonJS versions.
+A note that for now there is a small downside to sticking with CommonJS. It will continue to work [for the forseeable future](https://github.com/nodejs/node/issues/33954) in Node.js itself, but more modules on npm are switching to native ESM which is not very compatible with CommonJS. We may find ourselves forced to reconsider at some point if any of our key dependencies (e.g. Express) migrates to ESM-only and drop support for their old CommonJS versions.
 
 
 ## Tooling
@@ -52,7 +52,7 @@ When testing a monorepo, running tests and linting can happen in one of two ways
 
   2. Have tooling installed in each package and have commands in the top level package to run these
 
-We have opted to have tooling installed at the top level. This speeds up build times, because Jest has a non-trivial start up time and multiplying this by the number of packages can lead to a lot of overhead. This also means that the tooling is consistent between all of the different packages and upgrading the tooling happens in one place. There is more information on [how to run tests](./contributing.md#testing) in the contributing guide.
+We have opted to have tooling installed at the top level in most cases. This speeds up build times because multiplying startup times by the number of packages can lead to a lot of overhead. The exception is our tests, which are run via `node --test` from within each of the packages. There is more information on [how to run tests](./contributing.md#testing) in the contributing guide.
 
 ### Monorepo management
 

jsconfig.json

@@ -2,8 +2,10 @@
 	"compilerOptions": {
 		"alwaysStrict": true,
 		"checkJs": true,
+		"esModuleInterop": true,
 		"maxNodeModuleJsDepth": 0,
-		"module": "commonjs",
+		"module": "nodenext",
+		"moduleResolution": "nodenext",
 		"noEmit": true,
 		"noImplicitOverride": true,
 		"noImplicitThis": true,
@@ -12,7 +14,7 @@
 		"strictFunctionTypes": true,
 		"strictNullChecks": true,
 		"strictPropertyInitialization": true,
-		"target": "es2022",
+		"target": "es2024",
 		"useUnknownInCatchVariables": true,
 		"types": []
 	},