From 369fe95e3f42bda208e78c78c36be90db6bef81b Mon Sep 17 00:00:00 2001
From: David Glasser <glasser@davidglasser.net>
Date: Fri, 6 Jun 2025 22:38:17 -0700
Subject: [PATCH] Backport dual-build (and CI improvements) from express5

---
 .changeset/tame-carpets-beam.md |  5 +++++
 .github/workflows/ci.yml        | 11 +++++++++--
 package.json                    | 23 ++++++++++++++++++-----
 tsconfig.base.json              |  5 +++--
 tsconfig.build.cjs.json         |  7 +++++++
 tsconfig.build.esm.json         |  5 +++++
 tsconfig.build.json             | 12 +++++++++---
 7 files changed, 56 insertions(+), 12 deletions(-)
 create mode 100644 .changeset/tame-carpets-beam.md
 create mode 100644 tsconfig.build.cjs.json
 create mode 100644 tsconfig.build.esm.json

diff --git a/.changeset/tame-carpets-beam.md b/.changeset/tame-carpets-beam.md
new file mode 100644
index 0000000..5362ba9
--- /dev/null
+++ b/.changeset/tame-carpets-beam.md
@@ -0,0 +1,5 @@
+---
+'@as-integrations/express4': minor
+---
+
+The package is now built for both CJS and ESM, instead of only for CJS; this is the same build approach taken by `@apollo/server`. This provides better compatibility with ESM-based build systems.
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6c2f180..59aee80 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,7 +1,14 @@
 name: CI
 
 on:
-  pull_request
+  pull_request:
+    types:
+    - opened
+    - reopened
+    - synchronize
+    # So you can add a label to make it run, including no-changeset-needed
+    - labeled
+    - unlabeled
 
 jobs:
   build-and-test:
@@ -61,6 +68,7 @@ jobs:
   changeset:
     runs-on: ubuntu-latest
     name: Changesets
+    if: ${{ (! startsWith(github.head_ref, 'changeset-release/')) && (!contains(github.event.pull_request.labels.*.name, 'no-changeset-needed')) }}
     steps:
     - uses: actions/checkout@v4
       with:
@@ -68,4 +76,3 @@ jobs:
         fetch-depth: 0
     - uses: ./.github/actions/node
     - run: npm run changeset-check
-      if: ${{ ! startsWith(github.head_ref, 'changeset-release/') }}
diff --git a/package.json b/package.json
index 35ecfb8..56b53a6 100644
--- a/package.json
+++ b/package.json
@@ -12,18 +12,31 @@
   "bugs": {
     "url": "https://github.com/apollo-server-integrations/apollo-server-integration-express4/issues"
   },
-  "main": "dist/index.js",
-  "types": "dist/index.d.ts",
+  "type": "module",
+  "main": "dist/cjs/index.js",
+  "module": "dist/esm/index.js",
+  "types": "dist/esm/index.d.ts",
+  "exports": {
+    ".": {
+      "types": {
+        "require": "./dist/cjs/index.d.ts",
+        "default": "./dist/esm/index.d.ts"
+      },
+      "import": "./dist/esm/index.js",
+      "require": "./dist/cjs/index.js"
+    }
+  },
   "engines": {
     "node": ">=20"
   },
   "scripts": {
-    "build": "tsc --build tsconfig.build.json",
+    "compile": "tsc --build tsconfig.build.json",
+    "postcompile": "echo '{\"type\":\"module\"}' > dist/esm/package.json && echo '{\"type\":\"commonjs\"}' > dist/cjs/package.json",
     "clean": "git clean -dfqX",
-    "prepack": "npm run build",
+    "prepack": "npm run compile",
     "prettier-check": "prettier --check .",
     "prettier-fix": "prettier --write .",
-    "changeset-publish": "npm run build && changeset publish",
+    "changeset-publish": "npm run compile && changeset publish",
     "changeset-check": "changeset status --verbose --since=origin/main",
     "changeset-version": "changeset version && npm i",
     "spell-check": "cspell lint '**' --no-progress || (echo 'Add any real words to cspell-dict.txt.'; exit 1)",
diff --git a/tsconfig.base.json b/tsconfig.base.json
index 63a2e7d..cf4dc8b 100644
--- a/tsconfig.base.json
+++ b/tsconfig.base.json
@@ -1,9 +1,10 @@
 {
   "compilerOptions": {
+    "composite": true,
     "rootDir": "./src",
-    "outDir": "./dist",
+    "outDir": "./dist/esm",
     "target": "es2020",
-    "module": "commonjs",
+    "module": "esnext",
     "moduleResolution": "node",
     "esModuleInterop": true,
     "sourceMap": true,
diff --git a/tsconfig.build.cjs.json b/tsconfig.build.cjs.json
new file mode 100644
index 0000000..808c81b
--- /dev/null
+++ b/tsconfig.build.cjs.json
@@ -0,0 +1,7 @@
+{
+  "extends": "./tsconfig.build.esm.json",
+  "compilerOptions": {
+    "module": "commonjs",
+    "outDir": "./dist/cjs"
+  }
+}
\ No newline at end of file
diff --git a/tsconfig.build.esm.json b/tsconfig.build.esm.json
new file mode 100644
index 0000000..5106133
--- /dev/null
+++ b/tsconfig.build.esm.json
@@ -0,0 +1,5 @@
+{
+  "extends": "./tsconfig.base.json",
+  "include": ["src/**/*"],
+  "exclude": ["**/__tests__"]
+}
\ No newline at end of file
diff --git a/tsconfig.build.json b/tsconfig.build.json
index 555be5d..df681aa 100644
--- a/tsconfig.build.json
+++ b/tsconfig.build.json
@@ -1,5 +1,11 @@
 {
-  "extends": "./tsconfig.base.json",
-  "include": ["src/**/*"],
-  "exclude": ["**/__tests__"],
+  "compilerOptions": {
+    "composite": true
+  },
+  "files": [],
+  "include": [],
+  "references": [
+    { "path": "./tsconfig.build.esm.json" },
+    { "path": "./tsconfig.build.cjs.json" }
+  ]
 }