feat: 🎸 add support for env flag

packages/webpack-cli/README.md

@@ -39,6 +39,7 @@ Options
   -c, --config string      Provide path to a webpack configuration file
   -m, --merge string       Merge a configuration file using webpack-merge
   --progress               Print compilation progress during build
+  --env                    Environment passed to the configuration when it is a function
   --silent                 Disable any output that webpack makes
   --help                   Outputs list of supported flags
   -o, --output string      Output location of the file generated by webpack

packages/webpack-cli/lib/groups/ConfigGroup.js

@@ -83,10 +83,9 @@ class ConfigGroup extends GroupHelper {
         }
         const configPath = moduleObj.path;
         const configOptions = moduleObj.content;
-        if (configOptions.length > 0) {
-            newOptionsObject['options'] = configOptions;
-        } else if (typeof configOptions === 'function') {
-            const newOptions = configOptions();
+        if (typeof configOptions === 'function') {
+            // when config is a function, pass the env from args to the config function
+            const newOptions = configOptions(this.args.env);
             newOptionsObject['options'] = newOptions;
         } else {
             if (Array.isArray(configOptions) && !configOptions.length) {

packages/webpack-cli/lib/utils/cli-flags.js

@@ -240,6 +240,13 @@ module.exports = {
             group: DISPLAY_GROUP,
             description: 'It tells webpack to output all the information',
         },
+        {
+            name: 'env',
+            usage: '--env',
+            type: String,
+            group: CONFIG_GROUP,
+            description: 'Environment passed to the configuration when it is a function',
+        },
         /* 		{
 			name: "analyze",
 			type: Boolean,

test/config/type/function-with-env/a.js

@@ -0,0 +1 @@
+console.log('chuntaro');

test/config/type/function-with-env/function-with-env.test.js

@@ -0,0 +1,27 @@
+'use strict';
+const { stat } = require('fs');
+const { resolve } = require('path');
+const { run } = require('../../../utils/test-utils');
+
+describe('function configuration', () => {
+    it('is able to understand a configuration file as a function', () => {
+        const { stderr, stdout } = run(__dirname, ['--env', 'isProd']);
+        expect(stderr).toBeFalsy();
+        expect(stdout).toBeTruthy();
+        // Should generate the appropriate files
+        stat(resolve(__dirname, './bin/prod.js'), (err, stats) => {
+            expect(err).toBe(null);
+            expect(stats.isFile()).toBe(true);
+        });
+    });
+    it('is able to understand a configuration file as a function', () => {
+        const { stderr, stdout } = run(__dirname, ['--env', 'isDev']);
+        expect(stderr).toBeFalsy();
+        expect(stdout).toBeTruthy();
+        // Should generate the appropriate files
+        stat(resolve(__dirname, './bin/dev.js'), (err, stats) => {
+            expect(err).toBe(null);
+            expect(stats.isFile()).toBe(true);
+        });
+    });
+});

test/config/type/function-with-env/webpack.config.js

@@ -0,0 +1,17 @@
+module.exports = (env) => {
+    if (env === 'isProd') {
+        return {
+            entry: './a.js',
+            output: {
+                filename: 'prod.js',
+            },
+        };
+    }
+    return {
+        entry: './a.js',
+        mode: 'development',
+        output: {
+            filename: 'dev.js',
+        },
+    };
+};