fix: remove incorrect conditional exports handling

The conditional exports handling is not actually working because
equivalent logic isn't implemented in @rollup/plugin-node-resolve.

playground/TestModuleResolve.vue

@@ -7,9 +7,6 @@
   <div class="module-resolve-optimize" :class="optResolve">
     optimized {{ optResolve }}
   </div>
-  <div class="module-resolve-conditional" :class="conditionalExports">
-    conditional exports {{ conditionalExports }}
-  </div>
   <div class="index-resolve" :class="indexResolve">
     directory index resolve: {{ indexResolve }}
   </div>
@@ -22,7 +19,6 @@
 import { createRouter } from 'vue-router'
 import { createStore } from 'vuex'
 import { add } from 'lodash-es'
-import { test } from 'conditional-exports'
 import { foo } from './util'
 import { bar } from './util/bar.util'
 
@@ -32,7 +28,6 @@ export default {
       router: typeof createRouter === 'function' ? 'ok' : 'error',
       store: typeof createStore === 'function' ? 'ok' : 'error',
       optResolve: typeof add === 'function' ? 'ok' : 'error',
-      conditionalExports: test() ? 'ok' : 'error',
       indexResolve: foo() ? 'ok' : 'error',
       dotResolve: bar() ? 'ok' : 'error'
     }

playground/package.json

@@ -6,7 +6,6 @@
   },
   "dependencies": {
     "bootstrap": "link:../node_modules/bootstrap",
-    "conditional-exports": "link:./conditional-exports",
     "lodash-es": "link:../node_modules/lodash-es",
     "moment": "link:../node_modules/moment",
     "rewrite-optimized-test-package": "link:./rewrite-optimized/test-package"

src/node/resolver.ts

@@ -320,27 +320,19 @@ export function resolveNodeModule(
       return
     }
     let entryPoint: string | null = null
-    if (pkg.exports) {
-      if (typeof pkg.exports === 'string') {
-        entryPoint = pkg.exports
-      } else if (pkg.exports['.']) {
-        if (typeof pkg.exports['.'] === 'string') {
-          entryPoint = pkg.exports['.']
-        } else {
-          entryPoint = pkg.exports['.'].import
-        }
-      }
-    }
 
-    if (!entryPoint) {
-      for (const mainField of mainFields) {
-        if (pkg[mainField]) {
-          entryPoint = pkg[mainField]
-          break
-        }
+    for (const mainField of mainFields) {
+      if (pkg[mainField]) {
+        entryPoint = pkg[mainField]
+        break
       }
     }
 
+    // TODO properly support conditinal exports
+    // https://nodejs.org/api/esm.html#esm_conditional_exports
+    // Note: this would require @rollup/plugin-node-resolve to support it too
+    // or we will have to implement that logic in vite's own resolve plugin.
+
     // save resolved entry file path using the deep import path as key
     // e.g. foo/dist/foo.js
     // this is the path raw imports will be rewritten to, and is what will

test/test.js

@@ -105,7 +105,6 @@ describe('vite', () => {
       expect(await getText('.module-resolve-router')).toMatch('ok')
       expect(await getText('.module-resolve-store')).toMatch('ok')
       expect(await getText('.module-resolve-optimize')).toMatch('ok')
-      expect(await getText('.module-resolve-conditional')).toMatch('ok')
       expect(await getText('.index-resolve')).toMatch('ok')
       expect(await getText('.dot-resolve')).toMatch('ok')
     })