feat: support webpack profiling (#9804)

Co-authored-by: Martin Guillon <martin.guillon@akylas.fr>

packages/webpack5/__tests__/configuration/base.spec.ts

@@ -109,4 +109,14 @@ describe('base configuration', () => {
 			force: true,
 		});
 	});
+
+	it('supports --env.profile', () => {
+		init({
+			platform: 'ios',
+			profile: true,
+		});
+		const config = base(new Config());
+
+		expect(config.get('profile')).toBe(true);
+	});
 });

packages/webpack5/src/bin/index.ts

@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 
-import { redBright, green, greenBright } from 'chalk';
+import { redBright, green, greenBright, yellow } from 'chalk';
 import { program } from 'commander';
 import dedent from 'ts-dedent';
 import webpack from 'webpack';
@@ -115,6 +115,28 @@ program
 						errorDetails: env.verbose,
 					})
 				);
+
+				// if webpack profile is enabled we write the stats to a JSON file
+				if (configuration.profile || env.profile) {
+					console.log(
+						[
+							'',
+							'|',
+							`|  The build profile has been written to ${yellow(
+								'webpack.stats.json'
+							)}`,
+							`|  You can analyse the stats at ${green(
+								'https://webpack.github.io/analyse/'
+							)}`,
+							'|',
+							'',
+						].join('\n')
+					);
+					fs.writeFileSync(
+						path.join(process.cwd(), 'webpack.stats.json'),
+						JSON.stringify(stats.toJson())
+					);
+				}
 			}
 		};
 

packages/webpack5/src/configuration/base.ts

@@ -222,6 +222,11 @@ export default function (config: Config, env: IWebpackEnv = _env): Config {
 			});
 	});
 
+	// enable profiling with --env.profile
+	config.when(env.profile, (config) => {
+		config.profile(true);
+	});
+
 	// worker-loader should be declared before ts-loader
 	config.module
 		.rule('workers')

packages/webpack5/src/index.ts

@@ -43,6 +43,9 @@ export interface IWebpackEnv {
 	// enable verbose output
 	verbose?: boolean;
 
+	// enable webpack profiling
+	profile?: boolean;
+
 	// misc
 	replace?: string[] | string;
 	watchNodeModules?: boolean;