feat: truncate history file (#249)

* feat: truncate history file

* chore: husky

* chore: husky

.husky/.gitignore

@@ -0,0 +1 @@
+_

.husky/pre-commit

@@ -0,0 +1,4 @@
+#!/bin/sh
+. "$(dirname "$0")/_/husky.sh"
+
+yarn doc:toc && yarn doc:todos && git add .

README.md

@@ -323,8 +323,8 @@ Creates a new program. Options (object, optional) can contain these keys:
   displays program usage information.
 - `version` (boolean, default: true) adds `version` and `--version` to the
   program which displays program version from package.json.
-- `historyFile` (string, defaults: {homedir}/.bandersnatch_history) is a path to
-  the app history file.
+- `historyFile` (string | null, defaults: {homedir}/.bandersnatch_history) is a
+  path to the app history file. Set to NULL to disable.
 
 #### `program.description(description)`
 
@@ -680,7 +680,6 @@ Optionally deploy to GitHub, S3, etc. using your preferred CD method if needed.
 ## Todo
 
 - [ ] Better code coverage
-- [ ] History file cleanup (retain first x lines only)
 - [ ] Consider resolving ambiguity in _prompt_ param/method
 - [ ] Async autocomplete method
 - [ ] Choices autocompletion in REPL mode (open upstream PR in yargs)
@@ -694,6 +693,7 @@ Contributions are very welcome.
 git clone [email protected]:hongaar/bandersnatch.git
 cd bandersnatch
 yarn
+yarn husky install
 
 # Run an example
 yarn start examples/foo.ts

package.json

@@ -58,10 +58,5 @@
     "ts-jest": "26.5.6",
     "ts-node": "9.1.1",
     "typescript": "4.2.4"
-  },
-  "husky": {
-    "hooks": {
-      "pre-commit": "yarn doc:toc && yarn doc:todos"
-    }
   }
 }

src/history.ts

@@ -3,6 +3,8 @@ import os from 'os'
 import { REPLServer } from 'repl'
 import { Program } from './program'
 
+export const HISTSIZE = 500
+
 /**
  * Create new history instance.
  */
@@ -27,6 +29,18 @@ export class History {
       entry = entry.join(' ')
     }
 
+    // Truncate if needed and if possible
+    try {
+      const historyContents = fs.readFileSync(this.path, 'utf8').split(os.EOL)
+      if (historyContents.length > HISTSIZE) {
+        fs.writeFileSync(
+          this.path,
+          historyContents.slice(historyContents.length - HISTSIZE).join(os.EOL),
+          'utf8'
+        )
+      }
+    } catch (err) {}
+
     fs.appendFileSync(this.path, entry + os.EOL)
   }
 

src/index.ts

@@ -1,6 +1,7 @@
 export * from './argument'
 export * from './autocompleter'
 export * from './command'
+export * from './history'
 export * from './option'
 export * from './program'
 export * from './repl'

src/program.ts

@@ -50,11 +50,11 @@ type ProgramOptions = {
   version?: boolean
 
   /**
-   * Use this history file in REPL mode.
+   * Use this history file. Set to NULL to disable history file.
    *
    * Defaults to `{homedir}/.bandersnatch_history`.
    */
-  historyFile?: string
+  historyFile?: string | null
 }
 
 /**
@@ -70,23 +70,25 @@ function extractCommandFromProcess() {
 
 export class Program extends (EventEmitter as new () => TypedEventEmitter<Events>) {
   private commands: Command<any>[] = []
-  private history: History
+  private history?: History
   private replInstance?: Repl
 
   constructor(public options: ProgramOptions = {}) {
     super()
 
     // Set default prompt
-    if (!this.options.prompt) {
+    if (typeof this.options.prompt === 'undefined') {
       this.options.prompt = DEFAULT_PROMPT
     }
 
     // Set default historyFile
-    if (!this.options.historyFile) {
+    if (typeof this.options.historyFile === 'undefined') {
       this.options.historyFile = path.join(os.homedir(), DEFAULT_HISTORY_FILE)
     }
 
-    this.history = history(this)
+    if (this.options.historyFile !== null) {
+      this.history = history(this)
+    }
   }
 
   /**
@@ -228,7 +230,9 @@ export class Program extends (EventEmitter as new () => TypedEventEmitter<Events
         })
     )
 
-    this.replInstance.attachHistory(this.history)
+    if (this.history) {
+      this.replInstance.attachHistory(this.history)
+    }
     this.replInstance.start()
 
     return this.replInstance

src/repl.ts

@@ -50,10 +50,9 @@ export class Repl {
       ignoreUndefined: true,
     })
 
-    // Setup history 
+    // Setup history
     this.history?.hydrateReplServer(this.server)
 
-
     // Fixes bug with hidden cursor after enquirer prompt
     // @ts-ignore
     new Prompt().cursorShow()

tests/history.spec.ts

@@ -0,0 +1,62 @@
+import fs from 'fs'
+import os from 'os'
+import path from 'path'
+import { command, history, History, HISTSIZE, program } from '../src'
+
+// https://stackoverflow.com/a/52560084/938297
+function tmpFile(name = 'tmp_file', data = '', encoding = 'utf8') {
+  return new Promise<string>((resolve, reject) => {
+    const tempPath = path.join(os.tmpdir(), 'bandersnatch-')
+    fs.mkdtemp(tempPath, (err, folder) => {
+      if (err) return reject(err)
+
+      const file_name = path.join(folder, name)
+
+      fs.writeFile(file_name, data, encoding, (error_file) => {
+        if (error_file) return reject(error_file)
+
+        resolve(file_name)
+      })
+    })
+  })
+}
+
+test('history should return new History object', () => {
+  const app = program()
+
+  expect(history(app)).toBeInstanceOf(History)
+})
+
+test('commands should end up in history file', async () => {
+  const historyFile = await tmpFile('history_file')
+  const app = program({ historyFile }).add(command('test').action(() => {}))
+
+  await app.run('test')
+
+  expect(fs.readFileSync(historyFile, 'utf8')).toBe('test' + os.EOL)
+})
+
+test('history file should be truncated', async () => {
+  const historyFile = await tmpFile(
+    'history_file',
+    [...Array(HISTSIZE).keys()].join(os.EOL) + os.EOL
+  )
+  const app = program({ historyFile }).add(command('test').action(() => {}))
+
+  await app.run('test')
+
+  expect(fs.readFileSync(historyFile, 'utf8')).toBe(
+    [...Array(HISTSIZE).keys()].slice(1).join(os.EOL) + os.EOL + 'test' + os.EOL
+  )
+})
+
+test('commands should not end up in history file when disabled', async () => {
+  const historyFile = await tmpFile('history_file')
+  const app = program({ historyFile: null }).add(
+    command('test').action(() => {})
+  )
+
+  await app.run('test')
+
+  expect(fs.readFileSync(historyFile, 'utf8')).toBe('')
+})