Watch for file changes 👁️

src/__tests__/watchFiles.spec.ts → src/commands/lint/__tests__/watch-files.spec.ts

@@ -1,17 +1,22 @@
-import { readFile } from 'fs'
+import { readFile } from 'node:fs'
 
 import chokidar from 'chokidar'
 
-import { Events } from '@Types'
+import { EVENTS, fileChangeEvent, watchFiles } from '../watch-files'
 
-import { fileChangeEvent, watchFiles } from '../watchFiles'
-
-jest.mock('fs')
+jest.mock('node:fs')
 jest.mock('chokidar')
 
 describe('watchFiles', () => {
   let mockWatcher: chokidar.FSWatcher
 
+  const getEventPromise = (eventHandler: jest.Mock): Promise<void> => new Promise<void>((resolve) => {
+    fileChangeEvent.on(EVENTS.FILE_CHANGED, (params: Record<string, unknown>) => {
+      eventHandler(params)
+      resolve()
+    })
+  })
+
   const saveFile = (path: string, content: string, event: 'add' | 'change' | 'unlink') => {
     jest.mocked(readFile).mockImplementationOnce((_path: any, _encoding: any, callback?: (error: any, data: any) => void): void => {
       if (callback) {
@@ -40,7 +45,7 @@ describe('watchFiles', () => {
     fileChangeEvent.removeAllListeners()
   })
 
-  it('initialises chokidar with the correct file and ignore patterns', () => {
+  it('initialises chokidar with the file patterns and ignore patterns', () => {
     const filePatterns = ['**/*.ts']
     const ignorePatterns = ['node_modules']
 
@@ -53,103 +58,106 @@ describe('watchFiles', () => {
     })
   })
 
-  it('emits a "FILE_CHANGED" event when saving an existing file (because there is no hash map yet)', done => {
-    expect.assertions(1)
+  it('emits a "FILE_CHANGED" event when saving an existing file (because there is no hash map yet)', async () => {
+    expect.assertions(2)
 
+    const eventHandler = jest.fn()
+    const eventPromise = getEventPromise(eventHandler)
     const mockPath = 'mock/existing-file.ts'
 
-    fileChangeEvent.on(Events.FILE_CHANGED, params => {
-      expect(params).toStrictEqual({
-        message: `File \`${mockPath}\` has been changed.`,
-        path: mockPath,
-      })
-      done()
-    })
-
     watchFiles({ filePatterns: [mockPath], ignorePatterns: [] })
-
     saveFile(mockPath, 'hello-world', 'change')
+
+    await eventPromise
+
+    expect(eventHandler).toHaveBeenCalledTimes(1)
+    expect(eventHandler).toHaveBeenNthCalledWith(1, {
+      message: `File \`${mockPath}\` has been changed.`,
+      path: mockPath,
+    })
   })
 
-  it('emits a "FILE_CHANGED" event when saving a file if the file content changes', done => {
-    expect.assertions(2)
+  it('emits a "FILE_CHANGED" event when saving a file if the file content changes', async () => {
+    expect.assertions(3)
 
+    const eventHandler = jest.fn()
+    const eventPromise = getEventPromise(eventHandler)
     const mockPath = 'mock/update-file.ts'
 
-    fileChangeEvent.on(Events.FILE_CHANGED, params => {
-      expect(params).toStrictEqual({
-        message: `File \`${mockPath}\` has been changed.`,
-        path: mockPath,
-      })
-    })
-
     watchFiles({ filePatterns: [mockPath], ignorePatterns: [] })
-
     saveFile(mockPath, 'old-content', 'change') // First save - no hash map yet
     saveFile(mockPath, 'new-content', 'change') // Second save - content hash is different
 
-    setTimeout(() => {
-      done()
-    }, 100)
+    await eventPromise
+
+    expect(eventHandler).toHaveBeenCalledTimes(2)
+    expect(eventHandler).toHaveBeenNthCalledWith(1, {
+      message: `File \`${mockPath}\` has been changed.`,
+      path: mockPath,
+    })
+    expect(eventHandler).toHaveBeenNthCalledWith(2, {
+      message: `File \`${mockPath}\` has been changed.`,
+      path: mockPath,
+    })
   })
 
-  it('does not emit a "FILE_CHANGED" event when saving a file if the file content did not change', done => {
-    expect.assertions(1)
+  it('does not emit a "FILE_CHANGED" event when saving a file if the file content did not change', async () => {
+    expect.assertions(2)
 
+    const eventHandler = jest.fn()
+    const eventPromise = getEventPromise(eventHandler)
     const mockPath = 'mock/unchanged-file.ts'
 
-    fileChangeEvent.on(Events.FILE_CHANGED, params => {
-      expect(params).toStrictEqual({
-        message: `File \`${mockPath}\` has been changed.`,
-        path: mockPath,
-      })
-    })
-
     watchFiles({ filePatterns: [mockPath], ignorePatterns: [] })
-
     saveFile(mockPath, 'old-content', 'change') // First save - no hash map yet
     saveFile(mockPath, 'old-content', 'change') // Second save - content hash is the same
     saveFile(mockPath, 'old-content', 'change') // Third save - content hash is still the same
 
-    setTimeout(() => {
-      done()
-    }, 100)
+    await eventPromise
+
+    expect(eventHandler).toHaveBeenCalledTimes(1)
+    expect(eventHandler).toHaveBeenNthCalledWith(1, {
+      message: `File \`${mockPath}\` has been changed.`,
+      path: mockPath,
+    })
   })
 
-  it('emits a "FILE_CHANGED" event when a new file is added', done => {
-    expect.assertions(1)
+  it('emits a "FILE_CHANGED" event when a new file is added', async () => {
+    expect.assertions(2)
 
+    const eventHandler = jest.fn()
+    const eventPromise = getEventPromise(eventHandler)
     const mockPath = 'mock/new-file.ts'
 
-    fileChangeEvent.on(Events.FILE_CHANGED, params => {
-      expect(params).toStrictEqual({
-        message: `File \`${mockPath}\` has been added.`,
-        path: mockPath,
-      })
-      done()
-    })
-
     watchFiles({ filePatterns: [mockPath], ignorePatterns: [] })
-
     saveFile(mockPath, 'new-content', 'add')
+
+    await eventPromise
+
+    expect(eventHandler).toHaveBeenCalledTimes(1)
+    expect(eventHandler).toHaveBeenNthCalledWith(1, {
+      message: `File \`${mockPath}\` has been added.`,
+      path: mockPath,
+    })
   })
 
-  it('emits a "FILE_CHANGED" event when a file is removed', done => {
-    expect.assertions(1)
+  it('emits a "FILE_CHANGED" event when a file is removed', async () => {
+    expect.assertions(2)
 
+    const eventHandler = jest.fn()
+    const eventPromise = getEventPromise(eventHandler)
     const mockPath = 'mock/legacy-file.ts'
 
-    fileChangeEvent.on(Events.FILE_CHANGED, params => {
-      expect(params).toStrictEqual({
-        message: `File \`${mockPath}\` has been removed.`,
-        path: mockPath,
-      })
-      done()
-    })
-
     watchFiles({ filePatterns: [mockPath], ignorePatterns: [] })
-
     saveFile(mockPath, 'legacy-content', 'unlink')
+
+    await eventPromise
+
+    expect(eventHandler).toHaveBeenCalledTimes(1)
+    expect(eventHandler).toHaveBeenNthCalledWith(1, {
+      message: `File \`${mockPath}\` has been removed.`,
+      path: mockPath,
+    })
   })
 
 })

src/commands/lint/index.ts

@@ -4,8 +4,9 @@ import colourLog from '@Utils/colour-log'
 import { clearTerminal } from '@Utils/terminal'
 
 import { getFilePatterns } from './file-patterns'
+import { EVENTS, fileChangeEvent, watchFiles } from './watch-files'
 
-const lint = ({ clearCache, debug, emoji, eslintInclude, ignoreDirs, ignorePatterns, title, ...options }: LintOptions) => {
+const lint = ({ cache, clearCache, debug, emoji, eslintInclude, eslintUseLegacyConfig, fix, ignoreDirs, ignorePatterns, title, watch }: LintOptions) => {
   global.debug = debug
 
   clearTerminal()
@@ -21,7 +22,29 @@ const lint = ({ clearCache, debug, emoji, eslintInclude, ignoreDirs, ignorePatte
     ignorePatterns,
   })
 
-  console.log('Run Lint', options, filePatterns)
+  const lintOptions = {
+    cache,
+    eslintUseLegacyConfig,
+    filePatterns,
+    fix,
+    title,
+    watch,
+  }
+
+  console.log('Run Lint', lintOptions) // TODO: Run lint
+
+  if (watch) {
+    watchFiles({
+      filePatterns: Object.values(filePatterns.includePatterns).flat(),
+      ignorePatterns: filePatterns.ignorePatterns,
+    })
+
+    fileChangeEvent.on(EVENTS.FILE_CHANGED, ({ message }) => {
+      clearTerminal()
+      colourLog.info(`${message}\n`)
+      console.log('Run Lint', lintOptions) // TODO: Run lint
+    })
+  }
 }
 
 export default lint

src/watchFiles.ts → src/commands/lint/watch-files.ts

@@ -1,10 +1,12 @@
-import { createHash } from 'crypto'
-import { EventEmitter } from 'events'
-import { readFile } from 'fs'
+import { createHash } from 'node:crypto'
+import { EventEmitter } from 'node:events'
+import { readFile } from 'node:fs'
 
 import chokidar from 'chokidar'
 
-import { Events } from '@Types'
+enum EVENTS {
+  FILE_CHANGED = 'FILE_CHANGED',
+}
 
 interface WatchFiles {
   filePatterns: Array<string>
@@ -15,8 +17,6 @@ const fileChangeEvent = new EventEmitter()
 
 const fileHashes = new Map<string, string>()
 
-const getHash = (data: string) => createHash('md5').update(data).digest('hex')
-
 const watchFiles = ({ filePatterns, ignorePatterns }: WatchFiles) => {
   const watcher = chokidar.watch(filePatterns, {
     ignored: ignorePatterns,
@@ -25,18 +25,18 @@ const watchFiles = ({ filePatterns, ignorePatterns }: WatchFiles) => {
   })
 
   watcher.on('add', (path, _stats) => {
-    fileChangeEvent.emit(Events.FILE_CHANGED, {
+    fileChangeEvent.emit(EVENTS.FILE_CHANGED, {
       message: `File \`${path}\` has been added.`,
       path,
     })
   })
 
   watcher.on('change', (path, _stats) => {
     readFile(path, 'utf8', (_error, data) => {
-      const newHash = getHash(data)
+      const newHash = createHash('md5').update(data).digest('hex')
       if (fileHashes.get(path) !== newHash) {
         fileHashes.set(path, newHash)
-        fileChangeEvent.emit(Events.FILE_CHANGED, {
+        fileChangeEvent.emit(EVENTS.FILE_CHANGED, {
           message: `File \`${path}\` has been changed.`,
           path,
         })
@@ -45,14 +45,15 @@ const watchFiles = ({ filePatterns, ignorePatterns }: WatchFiles) => {
   })
 
   watcher.on('unlink', path => {
-    fileChangeEvent.emit(Events.FILE_CHANGED, {
+    fileChangeEvent.emit(EVENTS.FILE_CHANGED, {
       message: `File \`${path}\` has been removed.`,
       path,
     })
   })
 }
 
 export {
+  EVENTS,
   fileChangeEvent,
   watchFiles,
 }