feat(node-resolve): set development or production condition

The `'development'` or `'production'` condition will be set. If neither the `'development'` or `'production'` conditions are provided it will default to `production` - or `development` if `NODE_ENV` is set to a value other than `production`.

packages/node-resolve/README.md

@@ -53,7 +53,7 @@ This plugin supports the package entrypoints feature from node js, specified in
 Type: `Array[...String]`<br>
 Default: `[]`
 
-Additional conditions of the package.json exports field to match when resolving modules. By default, this plugin looks for the `['default', 'module', 'import']` conditions when resolving imports.
+Additional conditions of the package.json exports field to match when resolving modules. By default, this plugin looks for the `['default', 'module', 'import', 'development|production']` conditions when resolving imports. If neither the `development` or `production` conditions are provided it will default to `production` - or `development` if `NODE_ENV` is set to a value other than `production`.
 
 When using `@rollup/plugin-commonjs` v16 or higher, this plugin will use the `['default', 'module', 'require']` conditions when resolving require statements.
 

packages/node-resolve/src/index.js

@@ -52,8 +52,17 @@ export function nodeResolve(opts = {}) {
 
   const options = { ...defaults, ...opts };
   const { extensions, jail, moduleDirectories, modulePaths, ignoreSideEffectsForRoot } = options;
-  const conditionsEsm = [...baseConditionsEsm, ...(options.exportConditions || [])];
-  const conditionsCjs = [...baseConditionsCjs, ...(options.exportConditions || [])];
+  const exportConditions = options.exportConditions || [];
+  const devProdCondition =
+    exportConditions.includes('development') || exportConditions.includes('production')
+      ? []
+      : [
+          process.env.NODE_ENV && process.env.NODE_ENV !== 'production'
+            ? 'development'
+            : 'production'
+        ];
+  const conditionsEsm = [...baseConditionsEsm, ...exportConditions, ...devProdCondition];
+  const conditionsCjs = [...baseConditionsCjs, ...exportConditions, ...devProdCondition];
   const packageInfoCache = new Map();
   const idToPackageInfo = new Map();
   const mainFields = getMainFields(options);
@@ -171,7 +180,6 @@ export function nodeResolve(opts = {}) {
     const warn = (...args) => context.warn(...args);
     const isRequire = custom && custom['node-resolve'] && custom['node-resolve'].isRequire;
     const exportConditions = isRequire ? conditionsCjs : conditionsEsm;
-
     if (useBrowserOverrides && !exportConditions.includes('browser'))
       exportConditions.push('browser');
 

packages/node-resolve/test/fixtures/dev-prod-conditions.js

@@ -0,0 +1,3 @@
+import mode from 'dev-prod-conditions';
+
+export default mode;

packages/node-resolve/test/package-entry-points.js

@@ -413,3 +413,13 @@ test('custom condition takes precedence over browser field with `browser: true`'
 
   t.deepEqual(module.exports, 'FROM WEBWORKER CONDITION');
 });
+
+test('development condition is used when NODE_ENV is not production', async (t) => {
+  const bundle = await rollup({
+    input: 'dev-prod-conditions.js',
+    plugins: [nodeResolve()]
+  });
+  const { module } = await testBundle(t, bundle);
+
+  t.deepEqual(module.exports, 'DEV');
+});