feat: group module not found errors

src/formatters/moduleNotFound.js

@@ -1,33 +1,72 @@
 'use strict';
 const concat = require('../utils').concat;
 
-function dependenciesNotFound (count) {
+function moduleNotFound (count) {
   if (count === 1) {
-    return 'This dependency was not found in node_modules:';
+    return 'This module was not found:';
   }
 
-  return 'These dependencies were not found in node_modules:';
+  return 'These modules were not found:';
 }
 
-function forgetToInstall (count) {
-  if (count === 1) {
-    return 'Did you forget to run npm install --save for it?';
+function forgetToInstall (missingDependencies) {
+  const moduleNames = missingDependencies.map(missingDependency => missingDependency.module);
+
+  if (missingDependencies.length === 1) {
+    return `To install it, you can run: npm install --save ${moduleNames.join(' ')}`;
   }
 
-  return 'Did you forget to run npm install --save for them?';
+  return `To install them, you can run: npm install --save ${moduleNames.join(' ')}`;
+}
+
+function isRelative (module) {
+  return module.startsWith('./');
+}
+
+function groupModules (errors) {
+  const missingModule = new Map();
+
+  errors.forEach((error) => {
+    if (!missingModule.has(error.module)) {
+      missingModule.set(error.module, [])
+    }
+    missingModule.get(error.module).push(error);
+  });
+
+  return Array.from(missingModule.keys()).map(module => ({
+    module: module,
+    relative: isRelative(module),
+    errors: missingModule.get(module),
+  }));
+}
+
+function formatFileList (files) {
+  const length = files.length;
+  if (!length) return '';
+  return ` in ${files[0]}${files[1] ? `, ${files[1]}` : ''}${length > 2 ? ` and ${length - 2} other${length === 3 ? '' : 's'}` : ''}`;
+}
+
+function formatGroup (group) {
+  const files = group.errors.map(e => e.file).filter(Boolean);
+  return `* ${group.module}${formatFileList(files)}`;
 }
 
 function formatErrors (errors) {
   if (errors.length === 0) {
     return [];
   }
 
+  const groups = groupModules(errors);
+  const missingDependencies = groups.filter(group => !group.relative);
+
   return concat(
-    dependenciesNotFound(errors.length),
-    '',
-    errors.map(e =>`* ${e.module}${e.file ? ` in ${e.file}` : ''}`),
+    moduleNotFound(errors.length),
     '',
-    forgetToInstall(errors.length)
+    groups.map(formatGroup),
+    missingDependencies.length === 0 ? undefined : [
+      '',
+      forgetToInstall(missingDependencies)
+    ]
   );
 }
 

test/integration.spec.js

@@ -47,12 +47,12 @@ it('integration : module-errors', async() => {
   expect(logs).toEqual([
     'ERROR  Failed to compile with 2 errors',
     '',
-    'These dependencies were not found in node_modules:',
+    'These modules were not found:',
     '',
     '* ./non-existing in ./test/fixtures/module-errors/index.js',
     '* not-found in ./test/fixtures/module-errors/index.js',
     '',
-    'Did you forget to run npm install --save for them?'
+    'To install it, you can run: npm install --save not-found'
   ]);
 });
 
@@ -123,11 +123,11 @@ it('integration : webpack multi compiler : module-errors', async() => {
   expect(logs).toEqual([
     'ERROR  Failed to compile with 2 errors',
     '',
-    'These dependencies were not found in node_modules:',
+    'These modules were not found:',
     '',
     '* ./non-existing in ./test/fixtures/multi-compiler-module-errors/index.js',
     '* not-found in ./test/fixtures/multi-compiler-module-errors/index2.js',
     '',
-    'Did you forget to run npm install --save for them?'
+    'To install it, you can run: npm install --save not-found'
   ]);
 });

test/unit/formatters/moduleNotFound.spec.js

@@ -4,24 +4,69 @@ const expect = require('expect');
 it('Formats module-not-found errors', () => {
   const error = { type: 'module-not-found', module: 'redux' };
   expect(moduleNotFound([error])).toEqual([
-    'This dependency was not found in node_modules:',
+    'This module was not found:',
     '',
     '* redux',
     '',
-    'Did you forget to run npm install --save for it?'
+    'To install it, you can run: npm install --save redux'
   ]);
 });
 
 it('Groups all module-not-found into one', () => {
   const reduxError = { type: 'module-not-found', module: 'redux' };
   const reactError = { type: 'module-not-found', module: 'react' };
   expect(moduleNotFound([reduxError, reactError])).toEqual([
-    'These dependencies were not found in node_modules:',
+    'These modules were not found:',
     '',
     '* redux',
     '* react',
     '',
-    'Did you forget to run npm install --save for them?'
+    'To install them, you can run: npm install --save redux react'
+  ]);
+});
+
+it('Groups same module in module-not-found with 2 files', () => {
+  const reduxError = { type: 'module-not-found', module: 'redux' };
+  const reactError1 = { type: 'module-not-found', module: 'react', file: './src/file1.js' };
+  const reactError2 = { type: 'module-not-found', module: 'react', file: './src/file2.js' };
+  expect(moduleNotFound([reduxError, reactError1, reactError2])).toEqual([
+    'These modules were not found:',
+    '',
+    '* redux',
+    '* react in ./src/file1.js, ./src/file2.js',
+    '',
+    'To install them, you can run: npm install --save redux react'
+  ]);
+});
+
+it('Groups same module in module-not-found with 3 files', () => {
+  const reduxError = { type: 'module-not-found', module: 'redux' };
+  const reactError1 = { type: 'module-not-found', module: 'react', file: './src/file1.js' };
+  const reactError2 = { type: 'module-not-found', module: 'react', file: './src/file2.js' };
+  const reactError3 = { type: 'module-not-found', module: 'react', file: './src/file3.js' };
+  expect(moduleNotFound([reduxError, reactError1, reactError2, reactError3])).toEqual([
+    'These modules were not found:',
+    '',
+    '* redux',
+    '* react in ./src/file1.js, ./src/file2.js and 1 other',
+    '',
+    'To install them, you can run: npm install --save redux react'
+  ]);
+});
+
+it('Groups same module in module-not-found with 4 files', () => {
+  const reduxError = { type: 'module-not-found', module: 'redux' };
+  const reactError1 = { type: 'module-not-found', module: 'react', file: './src/file1.js' };
+  const reactError2 = { type: 'module-not-found', module: 'react', file: './src/file2.js' };
+  const reactError3 = { type: 'module-not-found', module: 'react', file: './src/file3.js' };
+  const reactError4 = { type: 'module-not-found', module: 'react', file: './src/file4.js' };
+  expect(moduleNotFound([reduxError, reactError1, reactError2, reactError3, reactError4])).toEqual([
+    'These modules were not found:',
+    '',
+    '* redux',
+    '* react in ./src/file1.js, ./src/file2.js and 2 others',
+    '',
+    'To install them, you can run: npm install --save redux react'
   ]);
 });