feat: add file system reader

Author: bejewel-kyoungmin

src/lib/library/library.factory.ts

@@ -13,7 +13,6 @@ import {
   url,
 } from '@angular-devkit/schematics';
 import { parse } from 'jsonc-parser';
-import { readFileSync } from 'fs';
 import { normalizeToKebabOrSnakeCase } from '../../utils/formatting';
 import {
   DEFAULT_LANGUAGE,
@@ -22,6 +21,7 @@ import {
   PROJECT_TYPE,
 } from '../defaults';
 import { LibraryOptions } from './library.schema';
+import { FileSystemReader } from '../readers';
 
 type UpdateJsonFn<T> = (obj: T) => T | void;
 interface TsConfigPartialType {
@@ -45,23 +45,20 @@ export function main(options: LibraryOptions): Rule {
 }
 
 function getDefaultLibraryPrefix(defaultLibraryPrefix = '@app') {
+  const fileSystemReader = new FileSystemReader(process.cwd())
+  const content: string | undefined = fileSystemReader.readSyncAnyOf([
+    'nest-cli.json',
+    '.nestcli.json',
+    '.nest-cli.json',
+    'nest.json',
+  ]);
+  
   try {
-    const nestCliJson = JSON.parse(
-      readFileSync('./nest-cli.json', 'utf-8'),
-    );
-    if (nestCliJson.hasOwnProperty('defaultLibraryPrefix')) {
-      return nestCliJson['defaultLibraryPrefix'];
+    const nestJson = JSON.parse(content || '{}');
+    if (nestJson.hasOwnProperty('defaultLibraryPrefix')) {
+      return nestJson['defaultLibraryPrefix'];
     }
   } catch (e) {
-    try {
-      const nestJson = JSON.parse(
-        readFileSync('./nest.json', 'utf-8'),
-      );
-      if (nestJson.hasOwnProperty('defaultLibraryPrefix')) {
-        return nestJson['defaultLibraryPrefix'];
-      }
-    } catch (e) {
-    }
   }
 
   return defaultLibraryPrefix;

src/lib/readers/file-system.reader.ts

@@ -0,0 +1,43 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import { Reader } from './reader';
+
+export class FileSystemReader implements Reader {
+  constructor(private readonly directory: string) {}
+  
+  public list(): Promise<string[]> {
+    return fs.promises.readdir(this.directory);
+  }
+  
+  public read(name: string): Promise<string> {
+    return fs.promises.readFile(path.join(this.directory, name), 'utf8');
+  }
+  
+  public readSync(name: string): string {
+    return fs.readFileSync(path.join(this.directory, name), 'utf8');
+  }
+  
+  public async readAnyOf(filenames: string[]): Promise<string | undefined> {
+    try {
+      for (const file of filenames) {
+        return await this.read(file);
+      }
+    } catch (err) {
+      return filenames.length > 0
+        ? await this.readAnyOf(filenames.slice(1, filenames.length))
+        : undefined;
+    }
+  }
+  
+  public readSyncAnyOf(filenames: string[]): string | undefined {
+    try {
+      for (const file of filenames) {
+        return this.readSync(file);
+      }
+    } catch (err) {
+      return filenames.length > 0
+        ? this.readSyncAnyOf(filenames.slice(1, filenames.length))
+        : undefined;
+    }
+  }
+}

src/lib/readers/index.ts

@@ -0,0 +1,2 @@
+export * from './reader';
+export * from './file-system.reader';

src/lib/readers/reader.ts

@@ -0,0 +1,7 @@
+export interface Reader {
+  list(): string[] | Promise<string[]>;
+  read(name: string): string | Promise<string>;
+  readSync(name: string): string;
+  readAnyOf(filenames: string[]): string | Promise<string | undefined>;
+  readSyncAnyOf(filenames: string[]): string | undefined;
+}

test/lib/readers/file-system.reader.spec.ts

@@ -0,0 +1,55 @@
+import * as fs from 'fs';
+import { FileSystemReader, Reader } from '../../../src/lib/readers';
+
+jest.mock('fs', () => ({
+  readFileSync: jest.fn().mockReturnValue('content'),
+  promises: {
+    readdir: jest.fn().mockResolvedValue([]),
+    readFile: jest.fn().mockResolvedValue('content'),
+  },
+}));
+
+const dir: string = process.cwd();
+const reader: Reader = new FileSystemReader(dir);
+
+describe('File System Reader', () => {
+  afterAll(() => {
+    jest.clearAllMocks();
+  });
+  it('should use fs.promises.readdir when list', async () => {
+    await reader.list();
+    expect(fs.promises.readdir).toHaveBeenCalled();
+  });
+  it('should use fs.promises.readFile when read', async () => {
+    await reader.read('filename');
+    expect(fs.promises.readFile).toHaveBeenCalled();
+  });
+  
+  describe('readAnyOf tests', () => {
+    it('should call readFile when running readAnyOf fn', async () => {
+      const filenames: string[] = ['file1', 'file2', 'file3'];
+      await reader.readAnyOf(filenames);
+      
+      expect(fs.promises.readFile).toHaveBeenCalled();
+    });
+    
+    it('should return undefined when no file is passed', async () => {
+      const content = await reader.readAnyOf([]);
+      expect(content).toEqual(undefined);
+    });
+  });
+  
+  describe('readSyncAnyOf tests', () => {
+    it('should call readFileSync when running readSyncAnyOf fn', async () => {
+      const filenames: string[] = ['file1', 'file2', 'file3'];
+      reader.readSyncAnyOf(filenames);
+      
+      expect(fs.readFileSync).toHaveBeenCalled();
+    });
+    
+    it('should return undefined when no file is passed', async () => {
+      const content = reader.readSyncAnyOf([]);
+      expect(content).toEqual(undefined);
+    });
+  });
+});