Format debug build using prettier

Author: andrewiggins

package-lock.json

@@ -99,6 +99,7 @@
 		"lodash.merge": "^4.6.2",
 		"magic-string": "^0.25.9",
 		"postcss": "^8.2.1",
+    "prettier": "^2.2.1",
 		"pretty-bytes": "^5.4.1",
 		"rollup": "^2.35.1",
 		"rollup-plugin-bundle-size": "^1.0.3",
@@ -131,7 +132,6 @@
 		"jest": "^26.6.3",
 		"lint-staged": "^10.5.3",
 		"npm-merge-driver-install": "^1.1.1",
-		"prettier": "^2.2.1",
 		"regenerator-runtime": "^0.13.7",
 		"rimraf": "^3.0.2",
 		"shell-quote": "^1.7.2",

package.json

@@ -40,6 +40,7 @@ import { getConfigFromPkgJson, getName } from './lib/package-info';
 import { shouldCssModules, cssModulesConfig } from './lib/css-modules';
 import { EOL } from 'os';
 import MagicString from 'magic-string';
+import prettier from 'prettier';
 
 // Extensions to use when resolving modules
 const EXTENSIONS = ['.ts', '.tsx', '.js', '.jsx', '.es6', '.es', '.mjs'];
@@ -660,7 +661,19 @@ function createConfig(options, entry, format, writeMeta) {
 						// Rollup 2 injects globalThis, which is nice, but doesn't really make sense for Microbundle.
 						// Only ESM environments necessitate globalThis, and UMD bundles can't be properly loaded as ESM.
 						// So we remove the globalThis check, replacing it with `this||self` to match Rollup 1's output:
-						renderChunk(code, chunk, opts) {
+						async renderChunk(code, chunk, opts) {
+							// Format debug builds with Prettier for better readability
+							if (format === 'debug') {
+								const formatted = prettier.format(code, {
+									parser: 'babel',
+									...pkg.prettier,
+								});
+								return {
+									code: formatted,
+									map: null,
+								};
+							}
+
 							if (opts.format === 'umd') {
 								// Can swap this out with MagicString.replace() when we bump it:
 								// https://github.com/developit/microbundle/blob/f815a01cb63d90b9f847a4dcad2a64e6b2f8596f/src/index.js#L657-L671

src/index.js

@@ -1750,8 +1750,8 @@ Build \\"debug-lib\\" to dist:
 279 B: debug-lib.esm.mjs.br
 415 B: debug-lib.umd.js.gz
 343 B: debug-lib.umd.js.br
-385 B: debug-lib.debug.js.gz
-320 B: debug-lib.debug.js.br"
+389 B: debug-lib.debug.js.gz
+323 B: debug-lib.debug.js.br"
 `;
 
 exports[`fixtures build debug with microbundle 2`] = `8`;
@@ -1779,10 +1779,11 @@ class UserManager {
   }
 
   async loadUsers() {
-    const allUsers = await Promise.all(this.users.map(u => fetchUserData(u.id)));
+    const allUsers = await Promise.all(
+      this.users.map((u) => fetchUserData(u.id))
+    );
     return allUsers;
   }
-
 }
 
 export { UserManager, createGreeting, fetchUserData };