feat: add TextFile adapters

Author: typicode

src/adapters/JSONFile.test.ts

@@ -12,24 +12,9 @@ test('should read and write', async (t) => {
   // Null if file doesn't exist
   t.is(await file.read(), null)
 
-  // Write obj
+  // Write
   t.is(await file.write(obj), undefined)
 
-  // Read obj
+  // Read
   t.deepEqual(await file.read(), obj)
 })
-
-test('should preserve order', async (t) => {
-  const filename = tempy.file()
-  const file = new JSONFile(filename)
-  const promises = []
-
-  let i = 0
-  for (; i <= 100; i++) {
-    promises.push(file.write(String(i)))
-  }
-
-  await Promise.all(promises)
-
-  t.is(await file.read(), String(i - 1))
-})

src/adapters/JSONFile.ts

@@ -1,34 +1,23 @@
-import fs from 'fs'
-import { Writer } from 'steno'
-
 import { Adapter } from '../Low.js'
+import { TextFile } from './TextFile.js'
 
 export class JSONFile<T> implements Adapter<T> {
-  private filename: string
-  private writer: Writer
+  private adapter: TextFile
 
   constructor(filename: string) {
-    this.filename = filename
-    this.writer = new Writer(filename)
+    this.adapter = new TextFile(filename)
   }
 
   async read(): Promise<T | null> {
-    let data
-
-    try {
-      data = await fs.promises.readFile(this.filename, 'utf-8')
-    } catch (e) {
-      if ((e as NodeJS.ErrnoException).code === 'ENOENT') {
-        return null
-      }
-      throw e
+    const data = await this.adapter.read()
+    if (data === null) {
+      return null
+    } else {
+      return JSON.parse(data) as T
     }
-
-    return JSON.parse(data) as T
   }
 
-  // eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
   write(obj: unknown): Promise<void> {
-    return this.writer.write(JSON.stringify(obj, null, 2))
+    return this.adapter.write(JSON.stringify(obj, null, 2))
   }
 }

src/adapters/JSONFileSync.test.ts

@@ -12,9 +12,9 @@ test('should read and write', (t) => {
   // Null if file doesn't exist
   t.is(file.read(), null)
 
-  // Write obj
+  // Write
   t.is(file.write(obj), undefined)
 
-  // Read obj
+  // Read
   t.deepEqual(file.read(), obj)
 })

src/adapters/JSONFileSync.ts

@@ -1,37 +1,23 @@
-import fs from 'fs'
-import path from 'path'
-
 import { SyncAdapter } from '../LowSync.js'
+import { TextFileSync } from './TextFileSync.js'
 
 export class JSONFileSync<T> implements SyncAdapter<T> {
-  private tempFilename: string
-  filename: string
+  private adapter: TextFileSync
 
   constructor(filename: string) {
-    this.filename = filename
-    this.tempFilename = path.join(
-      path.dirname(filename),
-      `.${path.basename(filename)}.tmp`,
-    )
+    this.adapter = new TextFileSync(filename)
   }
 
   read(): T | null {
-    let data
-
-    try {
-      data = fs.readFileSync(this.filename, 'utf-8')
-    } catch (e) {
-      if ((e as NodeJS.ErrnoException).code === 'ENOENT') {
-        return null
-      }
-      throw e
+    const data = this.adapter.read()
+    if (data === null) {
+      return null
+    } else {
+      return JSON.parse(data) as T
     }
-
-    return JSON.parse(data) as T
   }
 
   write(obj: T): void {
-    fs.writeFileSync(this.tempFilename, JSON.stringify(obj, null, 2))
-    fs.renameSync(this.tempFilename, this.filename)
+    this.adapter.write(JSON.stringify(obj, null, 2))
   }
 }

src/adapters/LocalStorage.test.ts

@@ -25,9 +25,9 @@ test('should read and write', (t) => {
   const obj = { a: 1 }
   const storage = new LocalStorage('key')
 
-  // Write obj
+  // Write
   t.is(storage.write(obj), undefined)
 
-  // Read obj
+  // Read
   t.deepEqual(storage.read(), obj)
 })

src/adapters/Memory.test.ts

@@ -10,9 +10,9 @@ test('should read and write', async (t) => {
   // Null by default
   t.is(await memory.read(), null)
 
-  // Write obj
+  // Write
   t.is(await memory.write(obj), undefined)
 
-  // Read obj
+  // Read
   t.deepEqual(await memory.read(), obj)
 })

src/adapters/MemorySync.test.ts

@@ -10,9 +10,9 @@ test('should read and write', (t) => {
   // Null by default
   t.is(memory.read(), null)
 
-  // Write obj
+  // Write
   t.is(memory.write(obj), undefined)
 
-  // Read obj
+  // Read
   t.deepEqual(memory.read(), obj)
 })

src/adapters/TextFile.test.ts

@@ -0,0 +1,35 @@
+import test from 'ava'
+import tempy from 'tempy'
+
+import { TextFile } from './TextFile.js'
+
+test('should read and write', async (t) => {
+  const str = 'foo'
+
+  const filename = tempy.file()
+  const file = new TextFile(filename)
+
+  // Null if file doesn't exist
+  t.is(await file.read(), null)
+
+  // Write
+  t.is(await file.write(str), undefined)
+
+  // Read
+  t.deepEqual(await file.read(), str)
+})
+
+test('should preserve order', async (t) => {
+  const filename = tempy.file()
+  const file = new TextFile(filename)
+  const promises = []
+
+  let i = 0
+  for (; i <= 100; i++) {
+    promises.push(file.write(String(i)))
+  }
+
+  await Promise.all(promises)
+
+  t.is(await file.read(), String(i - 1))
+})

src/adapters/TextFile.ts

@@ -0,0 +1,33 @@
+import fs from 'fs'
+import { Writer } from 'steno'
+
+import { Adapter } from '../Low.js'
+
+export class TextFile implements Adapter<string> {
+  private filename: string
+  private writer: Writer
+
+  constructor(filename: string) {
+    this.filename = filename
+    this.writer = new Writer(filename)
+  }
+
+  async read(): Promise<string | null> {
+    let data
+
+    try {
+      data = await fs.promises.readFile(this.filename, 'utf-8')
+    } catch (e) {
+      if ((e as NodeJS.ErrnoException).code === 'ENOENT') {
+        return null
+      }
+      throw e
+    }
+
+    return data
+  }
+
+  write(str: string): Promise<void> {
+    return this.writer.write(str)
+  }
+}

src/adapters/TextFileSync.test.ts

@@ -0,0 +1,20 @@
+import test from 'ava'
+import tempy from 'tempy'
+
+import { TextFileSync } from './TextFileSync.js'
+
+test('should read and write', (t) => {
+  const str = 'foo'
+
+  const filename = tempy.file()
+  const file = new TextFileSync(filename)
+
+  // Null if file doesn't exist
+  t.is(file.read(), null)
+
+  // Write
+  t.is(file.write(str), undefined)
+
+  // Read
+  t.deepEqual(file.read(), str)
+})