feat(webpack-cli): allow negative property for cli-flags

Author: snitin315

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

@@ -36,6 +36,14 @@ const basicOptions = [
         type: Number,
         description: 'number flag',
     },
+    {
+        name: 'neg-flag',
+        alias: 'b',
+        usage: '--neg-flag',
+        type: Boolean,
+        negative: true,
+        description: 'boolean flag',
+    },
     {
         name: 'string-flag',
         usage: '--string-flag <value>',
@@ -160,6 +168,26 @@ describe('arg-parser', () => {
         expect(warnMock.mock.calls.length).toEqual(0);
     });
 
+    it('parses --neg-flag', () => {
+        const res = argParser(basicOptions, ['--neg-flag'], true);
+        expect(res.unknownArgs.length).toEqual(0);
+        expect(res.opts).toEqual({
+            negFlag: true,
+            stringFlagWithDefault: 'default-value',
+        });
+        expect(warnMock.mock.calls.length).toEqual(0);
+    });
+
+    it('parses --no-neg-flag', () => {
+        const res = argParser(basicOptions, ['--no-neg-flag'], true);
+        expect(res.unknownArgs.length).toEqual(0);
+        expect(res.opts).toEqual({
+            negFlag: false,
+            stringFlagWithDefault: 'default-value',
+        });
+        expect(warnMock.mock.calls.length).toEqual(0);
+    });
+
     it('parses multi type flag as Boolean', () => {
         const res = argParser(basicOptions, ['--multi-type'], true);
         expect(res.unknownArgs.length).toEqual(0);

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

@@ -63,6 +63,11 @@ function argParser(options, args, argsOnly = false, name = '', helpFunction = un
             if (!option.multiple) {
                 // Prevent default behavior for standalone options
                 parserInstance.option(flagsWithType, option.description, option.defaultValue).action(() => {});
+                if (option.negative) {
+                    // commander requires explicitly adding the negated version of boolean flags
+                    const negatedFlag = `--no-${option.name}`;
+                    parserInstance.option(negatedFlag, `negates ${option.name}`);
+                }
             } else {
                 const multiArg = (value, previous = []) => previous.concat([value]);
                 parserInstance.option(flagsWithType, option.description, multiArg, option.defaultValue).action(() => {});

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

@@ -155,6 +155,7 @@ module.exports = {
             usage: '--hot',
             alias: 'h',
             type: Boolean,
+            negative: true,
             group: ADVANCED_GROUP,
             description: 'Enables Hot Module Replacement',
             link: 'https://webpack.js.org/concepts/hot-module-replacement/',
@@ -242,6 +243,7 @@ module.exports = {
             usage: '--stats <value>',
             type: [String, Boolean],
             group: DISPLAY_GROUP,
+            negative: true,
             description: 'It instructs webpack on how to treat the stats e.g. verbose',
             link: 'https://webpack.js.org/configuration/stats/#stats',
         },