refactor: human friendly formatting

package.json

@@ -90,6 +90,7 @@
   "dependencies": {
     "@rollup/pluginutils": "^5.1.0",
     "js-tokens": "^9.0.0",
+    "picocolors": "^1.0.1",
     "pkg-types": "^1.2.0",
     "unplugin": "^1.12.2"
   },

src/index.ts

@@ -3,6 +3,7 @@ import process from 'node:process'
 import { createFilter } from '@rollup/pluginutils'
 import escapeStringRegexp from 'escape-string-regexp'
 import jsTokens from 'js-tokens'
+import pc from 'picocolors'
 import { readPackageJSON, resolvePackageJSON } from 'pkg-types'
 import { createUnplugin, type UnpluginInstance } from 'unplugin'
 import { resolveOptions, type Options } from './core/options'
@@ -55,9 +56,14 @@ const plugin: UnpluginInstance<Options | undefined, false> = createUnplugin(
 
       buildEnd() {
         if (deps.size) {
-          const error = new Error(
-            `Unused dependencies found!\nDependencies: ${Array.from(deps).join(', ')}\nYou can remove them from ${pkgPath}`,
-          )
+          const message =
+            `Unused ${pc.cyan(deps.size)} dependencies found: \n\n` +
+            `${Array.from(deps)
+              .map((dep) => `${pc.yellow('-')} ${pc.bold(dep)}`)
+              .join('\n')}\n\n` +
+            `You can remove them from ${pkgPath}`
+
+          const error = new Error(message)
           if (options.level === 'error') {
             throw error
           } else {

tests/__snapshots__/rollup.test.ts.snap

@@ -6,32 +6,49 @@ var basic = \`import '@rollup/pluginutils'
 import 'js-tokens'
 import 'pkg-types'
 import 'unplugin'
+import 'picocolors'
 \`;
 
 export { basic as default };
 "
 `;
 
 exports[`rollup > error.js 1`] = `
-[Error: Unused dependencies found!
-Dependencies: js-tokens
+[Error: Unused 2 dependencies found: 
+
+- js-tokens
+- picocolors
+
 You can remove them from #CWD#/package.json]
 `;
 
 exports[`rollup > error-comment.js 1`] = `
-[Error: Unused dependencies found!
-Dependencies: @rollup/pluginutils, js-tokens, pkg-types
+[Error: Unused 4 dependencies found: 
+
+- @rollup/pluginutils
+- js-tokens
+- picocolors
+- pkg-types
+
 You can remove them from #CWD#/package.json]
 `;
 
 exports[`rollup > error-tsx.tsx 1`] = `
-[Error: Unused dependencies found!
-Dependencies: unplugin
+[Error: Unused 2 dependencies found: 
+
+- picocolors
+- unplugin
+
 You can remove them from #CWD#/package.json]
 `;
 
 exports[`rollup > error-vue.vue 1`] = `
-[Error: Unused dependencies found!
-Dependencies: @rollup/pluginutils, js-tokens, pkg-types
+[Error: Unused 4 dependencies found: 
+
+- @rollup/pluginutils
+- js-tokens
+- picocolors
+- pkg-types
+
 You can remove them from #CWD#/package.json]
 `;

tests/fixtures/basic.js

@@ -2,3 +2,4 @@ import '@rollup/pluginutils'
 import 'js-tokens'
 import 'pkg-types'
 import 'unplugin'
+import 'picocolors'