Set up vitest for graphql version 16 and 15 as well

Author: eddeee888

vitest.config.mts

@@ -1,18 +1,23 @@
 import { createRequire } from 'module';
 import { dirname, resolve } from 'path';
+import { versionInfo } from 'graphql';
 import { defineConfig } from 'vitest/config';
 
-// Use an absolute path to graphql/index.mjs so ALL imports (Vite-processed
-// and Node.js-native) resolve to the same ESM module in Node.js's module cache,
-// preventing graphql@17's devInstanceOf from detecting false cross-realm usage.
-const _require = createRequire(import.meta.url);
-// require.resolve('graphql') returns index.mjs in Node.js v24 (via module-sync condition)
-const graphqlIndexMjs = resolve(dirname(_require.resolve('graphql')), 'index.mjs');
-
 export const sharedConfig = defineConfig({
   resolve: {
     alias: {
-      graphql: graphqlIndexMjs,
+      graphql: (function resolveGraphQL() {
+        if (versionInfo.major < 17) {
+          return 'graphql/index.js';
+        }
+        // Use an absolute path to graphql/index.mjs so ALL imports (Vite-processed
+        // and Node.js-native) resolve to the same ESM module in Node.js's module cache,
+        // preventing graphql@17's devInstanceOf from detecting false cross-realm usage.
+        const _require = createRequire(import.meta.url);
+        // require.resolve('graphql') returns index.mjs in Node.js v24 (via module-sync condition)
+        const graphqlIndexMjs = resolve(dirname(_require.resolve('graphql')), 'index.mjs');
+        return graphqlIndexMjs;
+      })(),
     },
     tsconfigPaths: true,
   },