feat(webpack-cli): add arg postprocessing

packages/serve/src/startDevServer.ts

@@ -1,6 +1,5 @@
 import { utils } from 'webpack-cli';
 
-import createConfig from './createConfig';
 import getDevServerOptions from './getDevServerOptions';
 import mergeOptions from './mergeOptions';
 
@@ -15,7 +14,7 @@ const { logger } = utils;
  *
  * @returns {Object[]} array of resulting servers
  */
-export default function startDevServer(compiler, devServerArgs): object[] {
+export default function startDevServer(compiler, cliOptions): object[] {
     let isDevServer4 = false,
         devServerVersion,
         Server;
@@ -30,7 +29,6 @@ export default function startDevServer(compiler, devServerArgs): object[] {
     }
     isDevServer4 = devServerVersion.startsWith('4');
 
-    const cliOptions = createConfig(devServerArgs, isDevServer4);
     const devServerOptions = getDevServerOptions(compiler);
 
     const servers = [];

packages/webpack-cli/__tests__/arg-parser.test.js

@@ -96,6 +96,16 @@ const basicOptions = [
         multiple: true,
         description: 'multi flag',
     },
+    {
+        name: 'processor-flag',
+        usage: '--processor-flag',
+        type: Boolean,
+        description: 'flag with processor',
+        processor(opts) {
+            opts.processed = opts.processorFlag;
+            delete opts.processorFlag;
+        },
+    },
 ];
 
 const helpAndVersionOptions = basicOptions.slice(0);
@@ -421,4 +431,14 @@ describe('arg-parser', () => {
         });
         expect(warnMock.mock.calls.length).toEqual(0);
     });
+
+    it('parses --processor-flag', () => {
+        const res = argParser(basicOptions, ['--processor-flag'], true);
+        expect(res.unknownArgs.length).toEqual(0);
+        expect(res.opts).toEqual({
+            processed: true,
+            stringFlagWithDefault: 'default-value',
+        });
+        expect(warnMock.mock.calls.length).toEqual(0);
+    });
 });

packages/webpack-cli/lib/utils/arg-parser.js

@@ -28,6 +28,7 @@ const argParser = (options, args, argsOnly = false, name = '') => {
     }
 
     const parser = new commander.Command();
+    const processors = {};
 
     // Set parser name
     parser.name(name);
@@ -151,6 +152,15 @@ const argParser = (options, args, argsOnly = false, name = '') => {
             parserInstance.option(negatedFlag, `negates ${option.name}`).action(() => {});
         }
 
+        if (option.processor) {
+            // camel-case
+            const attributeName = option.name.split('-').reduce((str, word) => {
+                return str + word[0].toUpperCase() + word.slice(1);
+            });
+
+            processors[attributeName] = option.processor;
+        }
+
         return parserInstance;
     }, parser);
 
@@ -192,6 +202,8 @@ const argParser = (options, args, argsOnly = false, name = '') => {
     Object.keys(opts).forEach((key) => {
         if (opts[key] === undefined) {
             delete opts[key];
+        } else if (processors[key]) {
+            processors[key](opts);
         }
     });