build: migrate from yarn to npm

Author: mingchuno

.github/workflows/sanity.yml

@@ -32,13 +32,12 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
-          cache: 'yarn'
+          cache: 'npm'
       - name: Install dependencies
-        run: yarn install --frozen-lockfile
+        run: npm ci
       - name: Install MongoDB driver ${{ matrix.mongodb-driver }}
         run: |
-          npm install mongodb@${MONGODB_DRIVER_VERSION} --no-save --no-audit --legacy-peer-deps
-          rm -f package-lock.json npm-shrinkwrap.json
+          npm install mongodb@${MONGODB_DRIVER_VERSION} --no-save --no-package-lock --no-audit --legacy-peer-deps
       - name: Start MongoDB ${{ matrix.mongo-server }}
         run: docker compose up -d
       - name: Wait for MongoDB to accept connections
@@ -51,15 +50,15 @@ jobs:
           done
           echo "MongoDB failed to start" >&2
           exit 1
-      - run: yarn typecheck
-      - run: yarn test
+      - run: npm run typecheck
+      - run: npm test
       - name: Upload coverage
         if: matrix.node-version == '22.x' && matrix.mongodb-driver == '6' && matrix.mongo-server == '6.0'
-        run: yarn cov:send
+        run: npm run cov:send
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
       - name: Build artifacts
-        run: yarn build
+        run: npm run build
       - name: Tear down MongoDB
         if: always()
         run: docker compose down -v

.gitignore

@@ -6,7 +6,6 @@ node_modules
 src/**.js
 coverage
 *.log
-package-lock.json
 .eslintcache
 example/.env
 docker/tls/*

.husky/pre-commit

@@ -1,4 +1,4 @@
 #!/usr/bin/env sh
 [ "${HUSKY-}" = "0" ] && exit 0
 
-yarn lint-staged
+npx lint-staged

AGENTS.md

@@ -6,11 +6,11 @@ Welcome! This file keeps lightweight coordination notes for anyone (human or AI)
 
 1. Follow `docs/PLANS.md` for the prioritized maintenance backlog.
 2. When picking up a task, append a short status note under the relevant section in `docs/PLANS.md` (e.g. `- [started YYYY-MM-DD] <task>`), then remove or update it when you finish.
-3. Build pipeline now uses `tsdown` for dual ESM/CJS bundles into `dist/` plus `tsc` for typed transpilation (`yarn build` and `yarn typecheck`). Local sanity checks confirm `yarn build`, `yarn test:lint`, and `yarn test:prettier` pass (lint only warns on crypto key_size/iv_size/at_size camelCase). Full `yarn test` still needs a running MongoDB (e.g., docker compose up) until tests migrate to mongodb-memory-server.
+3. Build pipeline now uses `tsdown` for dual ESM/CJS bundles into `dist/` plus `tsc` for typed transpilation (`npm run build` and `npm run typecheck`). Local sanity checks confirm `npm run build`, `npm run test:lint`, and `npm run test:prettier` pass (lint only warns on crypto key_size/iv_size/at_size camelCase). Full `npm test` still needs a running MongoDB (e.g., docker compose up) until tests migrate to mongodb-memory-server.
 
 ## Workflow Expectations
 
-- Run `yarn install && yarn build && yarn test` locally before opening or updating a PR unless the change is docs-only.
+- Run `npm ci && npm run build && npm test` locally before opening or updating a PR unless the change is docs-only.
 - Record any assumptions, surprises, or TODOs at the bottom of the touched file(s) in `// TODO(agent): ...` comments or in `docs/PLANS.md`.
 - When working on a task, always follow PLAN, EDIT and REVIEW steps.
 - When working on a task, always check if CHANGELOG.md or README.md need updates. If encounter breaking changes, add a note to CHANGELOG.md and also create separate migration docs if needed.
@@ -23,3 +23,5 @@ Welcome! This file keeps lightweight coordination notes for anyone (human or AI)
 - For complex changes, request a human review to ensure the change aligns with project goals and also ask for clarification on any ambiguous points in the plan.
 
 Thanks for helping keep the project healthy!
+
+// TODO(agent): Husky install failed in this sandbox because `.git/config` was not writable; rerun `npm install` in a normal checkout to populate hooks.

MIGRATION_V4.md

@@ -2,22 +2,14 @@
 
 To migrate the library from V3 to V4, re-install the dependencies.
 
-If you are using `npm`
+Use your package manager (npm example shown):
 
 ```
 npm uninstall connect-mongo
 npm uninstall @types/connect-mongo
 npm install connect-mongo
 ```
 
-If you are using `yarn`
-
-```
-yarn remove connect-mongo
-yarn remove @types/connect-mongo
-yarn add connect-mongo
-```
-
 Next step is to import the dependencies
 
 Javascript:

README.md

@@ -39,7 +39,6 @@ MongoDB session store for [Connect](https://github.com/senchalabs/connect) and [
 
 ```
 npm install connect-mongo
-yarn add connect-mongo
 ```
 
 * Install `mongodb` alongside `connect-mongo`; it is a required peer dependency so you pick the driver version that matches your cluster.
@@ -308,14 +307,14 @@ One of the following options should be provided. If more than one option are pro
 ## Development
 
 ```
-yarn install
+npm install
 docker compose up -d
-yarn watch:test
+npm run watch:test
 ```
 
 ### TLS & SRV fixtures
 
-- Generate local certificates once with `yarn tls:setup` (drops files in `docker/tls`).
+- Generate local certificates once with `npm run tls:setup` (drops files in `docker/tls`).
 - Launch the optional TLS container with `docker compose -f docker-compose.yaml -f docker-compose.tls.yaml --profile tls up -d`.
 - Copy `example/.env.example` to `example/.env` and point `MONGO_URL` to the TLS port (`mongodb://root:example@127.0.0.1:27443/example-db?authSource=admin`). Add `MONGO_TLS_CA_FILE=../docker/tls/ca.crt` so the driver trusts the self-signed CA. Set `MONGO_TLS_CERT_KEY_FILE=../docker/tls/client.pem` if you need mutual TLS.
 - To exercise SRV/TLS against a managed cluster (Atlas, DocumentDB, CosmosDB), set `MONGO_URL` to your `mongodb+srv://` string and either `MONGO_TLS_CA_FILE` or `NODE_EXTRA_CA_CERTS` to the provider CA bundle. The example scripts automatically reuse those settings in every variant (plain JS, Mongoose, and TS).
@@ -325,12 +324,12 @@ yarn watch:test
 ```
 # from the repo root
 cp example/.env.example example/.env
-yarn link
+npm link
 cd example
-yarn link "connect-mongo"   # optional if you want live code from this checkout
-yarn install
-yarn start:js
-# or yarn start:mongoose / yarn start:ts
+npm link "connect-mongo"   # optional if you want live code from this checkout
+npm install
+npm run start:js
+# or npm run start:mongoose / npm run start:ts
 ```
 
 After the first run you can edit `example/.env` to swap between the local docker fixture, the TLS profile, or any `mongodb+srv://` cluster without changing the code.
@@ -340,7 +339,7 @@ After the first run you can edit `example/.env` to swap between the local docker
 Until the GitHub release workflow lands, do the manual flow:
 
 1. Bump version, update `CHANGELOG.md` and README. Commit and push.
-2. Run `yarn test && yarn build` (build uses `tsdown` to emit dual ESM/CJS bundles to `dist/`).
+2. Run `npm test && npm run build` (build uses `tsdown` to emit dual ESM/CJS bundles to `dist/`).
 3. Publish: `npm publish`
 4. Tag: `git tag vX.Y.Z && git push --tags`
 

docs/PLANS.md

@@ -8,9 +8,10 @@
 
 - Tooling & CI
   - Rework integration helpers: replace the broken `check-cli`/`diff-integration-tests`, document a safe reset workflow, and migrate `test:integration` to mongodb-memory-server.
-  - CI matrix should cover MongoDB driver ranges via temp `yarn add --no-lockfile --dev mongodb@x`, exercise MongoDB 7.x containers with health checks, and always run `docker compose down` in a finally step.
-  - Expand coverage for crypto, autoRemove, touchAfter, and transformId using mongodb-memory-server; continue the started live-Mongo upgrade compat test (5.1.0 ➜ current) exposed as `yarn test:compat`.
+  - CI matrix should cover MongoDB driver ranges via temp `npm install mongodb@x --no-save --no-package-lock`, exercise MongoDB 7.x containers with health checks, and always run `docker compose down` in a finally step.
+  - Expand coverage for crypto, autoRemove, touchAfter, and transformId using mongodb-memory-server; continue the started live-Mongo upgrade compat test (5.1.0 ➜ current) exposed as `npm run test:compat`.
   - Automate releases with standard-version + GitHub Actions to build, test, publish, upload coverage, and tag.
+  - [done 2025-11-24] Migrate tooling from yarn to npm.
 
 - Docs & Community
   - Refresh README badges/compatibility matrix to match supported Node 20/22/24, MongoDB server 4.4–8.0, driver >=5<8, and express support; link to CI results.

example/.env.example

@@ -7,7 +7,7 @@ SESSION_SECRET=connect-mongo-example-secret
 # SESSION_CRYPTO_SECRET=replace-with-a-long-secret
 # MONGO_MAX_POOL_SIZE=10
 
-# TLS flags (after running `yarn tls:setup`)
+# TLS flags (after running `npm run tls:setup`)
 # MONGO_TLS_CA_FILE=../docker/tls/ca.crt
 # MONGO_TLS_CERT_KEY_FILE=../docker/tls/client.pem
 # MONGO_TLS_ALLOW_INVALID_CERTIFICATES=false