WIP: feat: Init for currently exising folders

__e2e__/init.test.ts

@@ -39,12 +39,38 @@ afterEach(() => {
   cleanupSync(DIR);
 });
 
-test('init fails if the directory already exists', () => {
+test('init passes if the directory already exists', () => {
   fs.mkdirSync(path.join(DIR, 'TestInit'));
 
-  const {stderr} = runCLI(DIR, ['init', 'TestInit'], {expectedFailure: true});
+  const {stdout} = runCLI(DIR, ['init', 'TestInit']);
+
+  expect(stdout).toContain('Run instructions');
+});
+
+test('init fails if the directory contains conflicting files/sub-directories', () => {
+  const projectName = 'TestInit';
+  const directoryName = 'custom-path';
+  const targetDirectory = path.resolve(DIR, directoryName);
+  // pre existing directory structure
+  writeFiles(targetDirectory, {
+    'package.json': '',
+    'package-lock.json': '',
+    'yarn.lock': '',
+    'babel.config.js': '',
+    'android/gradlew': '',
+    [`ios/${projectName}/AppDelegate.h`]: '',
+  });
+
+  const {stderr} = runCLI(
+    DIR,
+    ['init', '--directory', directoryName, projectName],
+    {expectedFailure: true},
+  );
+
+  expect(stderr).not.toContain('ios');
+  expect(stderr).toContain('package.json');
   expect(stderr).toContain(
-    'error Cannot initialize new project because directory "TestInit" already exists.',
+    'Either try using a new directory name, or remove the files listed above.',
   );
 });
 

packages/cli/src/commands/init/constants.ts

@@ -0,0 +1,14 @@
+export const UNDERSCORED_DOTFILES = [
+  'buckconfig',
+  'eslintrc.js',
+  'flowconfig',
+  'gitattributes',
+  'gitignore',
+  'prettierrc.js',
+  'watchmanconfig',
+  'editorconfig',
+  'bundle',
+  'ruby-version',
+  'node-version',
+  'xcode.env',
+];

packages/cli/src/commands/init/editTemplate.ts

@@ -6,6 +6,7 @@ import walk from '../../tools/walk';
 // `gracefulify` does not support patching `fs.promises`. Use `fs-extra`, which
 // exposes its own promise-based interface over `graceful-fs`.
 import fs from 'fs-extra';
+import {UNDERSCORED_DOTFILES} from './constants';
 
 interface PlaceholderConfig {
   projectName: string;
@@ -58,21 +59,6 @@ function shouldIgnoreFile(filePath: string) {
   return filePath.match(/node_modules|yarn.lock|package-lock.json/g);
 }
 
-const UNDERSCORED_DOTFILES = [
-  'buckconfig',
-  'eslintrc.js',
-  'flowconfig',
-  'gitattributes',
-  'gitignore',
-  'prettierrc.js',
-  'watchmanconfig',
-  'editorconfig',
-  'bundle',
-  'ruby-version',
-  'node-version',
-  'xcode.env',
-];
-
 async function processDotfiles(filePath: string) {
   const dotfile = UNDERSCORED_DOTFILES.find((e) => filePath.includes(`_${e}`));
 

packages/cli/src/commands/init/errors/ConflictingFilesError.ts

@@ -0,0 +1,14 @@
+export default class ConflictingFilesError extends Error {
+  constructor(directoryName: string, files: string[]) {
+    let errorString = '';
+
+    errorString += `The directory ${directoryName} contains files that could conflict:\n`;
+    for (const file of files) {
+      errorString += `- ${file}\n`;
+    }
+    errorString +=
+      'Either try using a new directory name, or remove the files listed above.';
+
+    super(errorString);
+  }
+}

packages/cli/src/commands/init/init.ts

@@ -2,7 +2,6 @@ import os from 'os';
 import path from 'path';
 import fs from 'fs-extra';
 import {validateProjectName} from './validate';
-import DirectoryAlreadyExistsError from './errors/DirectoryAlreadyExistsError';
 import printRunInstructions from './printRunInstructions';
 import {
   CLIError,
@@ -20,6 +19,9 @@ import {changePlaceholderInTemplate} from './editTemplate';
 import * as PackageManager from '../../tools/packageManager';
 import {installPods} from '@react-native-community/cli-doctor';
 import banner from './banner';
+import ConflictingFilesError from './errors/ConflictingFilesError';
+import walk from '../../tools/walk';
+import {UNDERSCORED_DOTFILES} from './constants';
 import TemplateAndVersionError from './errors/TemplateAndVersionError';
 
 const DEFAULT_VERSION = 'latest';
@@ -47,22 +49,62 @@ function doesDirectoryExist(dir: string) {
   return fs.existsSync(dir);
 }
 
-async function setProjectDirectory(directory: string) {
-  if (doesDirectoryExist(directory)) {
-    throw new DirectoryAlreadyExistsError(directory);
-  }
+function getDirectoryFilesRecursive(dir: string): string[] {
+  return walk(dir, true)
+    .map((file) => file.replace(dir, ''))
+    .filter(Boolean);
+}
 
-  try {
-    fs.mkdirSync(directory, {recursive: true});
-    process.chdir(directory);
-  } catch (error) {
-    throw new CLIError(
-      'Error occurred while trying to create project directory.',
-      error,
+function checkProjectDirectoryForConflictsWithTemplate(
+  projectDirectory: string,
+  templateName: string,
+  templateDir: string,
+  templateSourceDir: string,
+) {
+  const projectDirectoryFiles = getDirectoryFilesRecursive(projectDirectory);
+
+  const templatePath = path.resolve(
+    templateSourceDir,
+    'node_modules',
+    templateName,
+    templateDir,
+  );
+  const templateFiles: string[] = [];
+  getDirectoryFilesRecursive(templatePath).forEach((fileName) => {
+    templateFiles.push(fileName);
+
+    // We first copy template into project folder, and then we rename underscored files,
+    // so here we are taking both options into account
+    const dotfile = UNDERSCORED_DOTFILES.find((e) =>
+      fileName.includes(`_${e}`),
     );
+    if (dotfile) {
+      templateFiles.push(dotfile);
+    }
+  });
+
+  const conflictingFiles: string[] = projectDirectoryFiles.filter((fileName) =>
+    templateFiles.includes(fileName),
+  );
+  if (conflictingFiles.length > 0) {
+    throw new ConflictingFilesError(projectDirectory, conflictingFiles);
   }
+}
 
-  return process.cwd();
+async function setProjectDirectory(directory: string) {
+  const projectDirectory = path.join(process.cwd(), directory);
+  if (!doesDirectoryExist(projectDirectory)) {
+    try {
+      fs.mkdirSync(directory, {recursive: true});
+    } catch (error) {
+      throw new CLIError(
+        'Error occurred while trying to create project directory.',
+        error,
+      );
+    }
+  }
+  process.chdir(projectDirectory);
+  return projectDirectory;
 }
 
 function getTemplateName(cwd: string) {
@@ -104,6 +146,14 @@ async function createFromTemplate({
 
     const templateName = getTemplateName(templateSourceDir);
     const templateConfig = getTemplateConfig(templateName, templateSourceDir);
+
+    await checkProjectDirectoryForConflictsWithTemplate(
+      projectDirectory,
+      templateName,
+      templateConfig.templateDir,
+      templateSourceDir,
+    );
+
     await copyTemplate(
       templateName,
       templateConfig.templateDir,

packages/cli/src/tools/walk.ts

@@ -9,16 +9,16 @@
 import fs from 'fs';
 import path from 'path';
 
-function walk(current: string): string[] {
+function walk(current: string, filesOnly: boolean = false): string[] {
   if (!fs.lstatSync(current).isDirectory()) {
     return [current];
   }
 
   const files = fs
     .readdirSync(current)
-    .map((child) => walk(path.join(current, child)));
+    .map((child) => walk(path.join(current, child), filesOnly));
   const result: string[] = [];
-  return result.concat.apply([current], files);
+  return result.concat.apply(!filesOnly ? [current] : [], files);
 }
 
 export default walk;