fix: restore the types conditions in the published exports map

.changeset/wild-pugs-resolve.md

@@ -0,0 +1,25 @@
+---
+'graphql-modules': patch
+---
+
+Restore the `types` conditions in the published `exports` map.
+
+`package.json` has declared `exports["."].types` and `exports["./*"].types` for
+years, but `bob build` discards them: its `rewriteExports` rebuilds every entry
+as `{ require, import }` only. Every published tarball up to and including
+3.1.2 therefore ships an `exports` map with no `types` condition, which makes
+the declarations unreachable under `moduleResolution` `bundler`, `node16` and
+`nodenext` — TypeScript reports
+
+```
+error TS7016: Could not find a declaration file for module 'graphql-modules'.
+  There are types at '.../graphql-modules/index.d.ts', but this result could
+  not be resolved when respecting package.json "exports".
+```
+
+Only the legacy `node10` resolver worked, because it reads the top-level
+`typings` field and ignores `exports` entirely.
+
+The conditions are now reinstated in `scripts/fix-async-context.js`, which
+already post-processes `dist/package.json` for the same class of loss — bob also
+strips the `imports` field. Fixes the problem reported in #2480.

scripts/fix-async-context.js

@@ -3,6 +3,9 @@ const path = require('path');
 
 const __project = path.resolve(__dirname, '..');
 
+// bob publishes from this directory, and rewrites exports paths relative to it.
+const DIST_DIR = 'dist';
+
 console.log('Fixing async context imports in dist package.json...');
 
 const distPkg = JSON.parse(
@@ -48,6 +51,35 @@ for (const file of [node, browser]) {
 
 console.log('Updating imports field in dist package.json...');
 distPkg.imports = srcPkg.imports;
+
+// Restore the "types" conditions as well. bob's rewriteExports rebuilds every
+// entry as { require, import } only, so any "types" condition in the source
+// exports map is dropped on the way to dist -- even though package.json has
+// declared it for years. Without it, a consumer on moduleResolution
+// bundler/node16/nodenext cannot see the declarations at all: only the legacy
+// node10 resolver can, via "typings". That is the cause of #2480 and #2686.
+console.log('Restoring types conditions in dist package.json exports...');
+for (const [subpath, srcCondition] of Object.entries(srcPkg.exports || {})) {
+  if (
+    !srcCondition ||
+    typeof srcCondition !== 'object' ||
+    !srcCondition.types
+  ) {
+    continue;
+  }
+
+  const distCondition = distPkg.exports && distPkg.exports[subpath];
+  if (!distCondition || typeof distCondition !== 'object') {
+    continue;
+  }
+
+  // "types" first: that is the documented order, and it keeps the condition
+  // ahead of the runtime ones for any resolver that short-circuits.
+  distPkg.exports[subpath] = {
+    types: srcCondition.types.replace(`${DIST_DIR}/`, ''),
+    ...distCondition,
+  };
+}
 fs.writeFileSync(
   path.join(__project, 'packages', 'graphql-modules', 'dist', 'package.json'),
   JSON.stringify(distPkg, null, 2) + '\n'