Add "type": "module" to @apollo/client/core and friends

config/helpers.ts

@@ -23,6 +23,7 @@ export function eachFile(dir: string, callback: (
 
         // Avoid re-transforming CommonJS bundle files.
         if (relPath.endsWith(".cjs.js")) return;
+        if (relPath.endsWith(".cjs")) return;
 
         // Avoid re-transforming CommonJS bundle files.
         if (relPath.endsWith(".min.js")) return;

config/prepareDist.js

@@ -69,7 +69,8 @@ entryPoints.forEach(function buildPackageJson({
     path.join(distRoot, ...dirs, 'package.json'),
     JSON.stringify({
       name: path.posix.join('@apollo', 'client', ...dirs),
-      main: `${bundleName}.cjs.js`,
+      type: "module",
+      main: `${bundleName}.cjs`,
       module: 'index.js',
       types: 'index.d.ts',
       sideEffects,

config/resolveModuleIds.ts

@@ -54,20 +54,44 @@ function isRelative(id: string) {
 }
 
 function normalizeSourceString(file: string, source?: Node | null) {
-  if (source && n.StringLiteral.check(source) && isRelative(source.value)) {
+  if (source && n.StringLiteral.check(source)) {
     try {
-      source.value = normalizeId(source.value, file);
+      source.value = isRelative(source.value)
+        ? normalizeId(source.value, file)
+        : normalizeNonRelativeId(source.value, file);
     } catch (error) {
-      console.error(`Failed to resolve ${source.value} in ${file}`);
+      console.error(`Failed to resolve ${source.value} in ${file} with error ${error}`);
       process.exit(1);
     }
   }
 }
 
+function normalizeNonRelativeId(id: string, file: string) {
+  const normal = normalizeId(id, file);
+  const normalParts = normal.split("/");
+  const sourceParts = id.split("/");
+  const nodeModulesIndex = normalParts.lastIndexOf("node_modules");
+  if (
+    nodeModulesIndex >= 0 &&
+    normalParts[nodeModulesIndex + 1] === sourceParts[0]
+  ) {
+    const bareModuleIdentifier =
+      normalParts.slice(nodeModulesIndex + 1).join("/");
+    if (normal === normalizeId(bareModuleIdentifier, file)) {
+      return bareModuleIdentifier;
+    }
+    console.error(`Leaving ${id} import in ${file} unchanged because ${
+      bareModuleIdentifier
+    } does not resolve to the same module`);
+  }
+  return id;
+}
+
 function normalizeId(id: string, file: string) {
   const basedir = path.dirname(file);
   const absPath = resolve.sync(id, {
     basedir,
+    extensions: [".mjs", ".js"],
     packageFilter(pkg) {
       return pkg.module ? {
         ...pkg,

config/rollup.config.js

@@ -77,7 +77,7 @@ function prepareCJSMinified(input) {
   return {
     input,
     output: {
-      file: input.replace('.js', '.min.js'),
+      file: input.replace('.cjs', '.min.cjs'),
       format: 'cjs',
     },
     plugins: [
@@ -108,7 +108,7 @@ function prepareBundle({
       return isExternal(id, parentId, true);
     },
     output: {
-      file: `${dir}/${bundleName}.cjs.js`,
+      file: `${dir}/${bundleName}.cjs`,
       format: 'cjs',
       sourcemap: true,
       exports: 'named',
@@ -125,10 +125,10 @@ export default [
   // Convert the ESM entry point to a single CJS bundle.
   prepareCJS(
     './dist/core/index.js',
-    './dist/apollo-client.cjs.js',
+    './dist/apollo-client.cjs',
   ),
   // Minify that single CJS bundle.
   prepareCJSMinified(
-    './dist/apollo-client.cjs.js',
+    './dist/apollo-client.cjs',
   ),
 ];

config/version.js

@@ -31,7 +31,7 @@ switch (process.argv[2]) {
     const {
       ApolloClient,
       InMemoryCache,
-    } = require(path.join(distRoot, "core", "core.cjs.js"));
+    } = require(path.join(distRoot, "core", "core.cjs"));
 
     // Though this may seem like overkill, verifying that ApolloClient is
     // constructible in Node.js is actually pretty useful, too!
@@ -43,15 +43,15 @@ switch (process.argv[2]) {
     // the client might have acquired during its construction.
     client.stop();
 
-    // The CommonJS dist/core/core.cjs.js file is generated from ESM modules
-    // generated by tsc, including dist/version.js, so verifying core.cjs.js
-    // exports an ApolloClient class that defines client.version also serves
-    // to verify that dist/version.js must have been correctly updated,
-    // which is convenient because dist/version.js uses ECMAScript module
-    // syntax, and is thus not importable in all versions of Node.js.
+    // The CommonJS dist/core/core.cjs file is generated from ESM modules
+    // generated by tsc, including dist/version.js, so verifying core.cjs
+    // exports an ApolloClient class that defines client.version also serves to
+    // verify that dist/version.js must have been correctly updated, which is
+    // convenient because dist/version.js uses ECMAScript module syntax, and is
+    // thus not importable in all versions of Node.js.
     assert.strictEqual(
       client.version, version,
-      "Failed to update dist/version.js and dist/core/core.cjs.js",
+      "Failed to update dist/version.js and dist/core/core.cjs",
     );
 
     break;

package.json

@@ -13,7 +13,7 @@
   ],
   "author": "opensource@apollographql.com",
   "license": "MIT",
-  "main": "./dist/main.cjs.js",
+  "main": "./dist/main.cjs",
   "module": "./dist/index.js",
   "types": "./dist/index.d.ts",
   "sideEffects": false,
@@ -54,7 +54,7 @@
   "bundlesize": [
     {
       "name": "apollo-client",
-      "path": "./dist/apollo-client.cjs.min.js",
+      "path": "./dist/apollo-client.min.cjs",
       "maxSize": "24.6 kB"
     }
   ],