Convert @bugsnag/plugin-server-session to TypeScript (#2514)

* convert server session to typescript

* update package-lock

* add type declaration file for backo

* update types

* update types

* update types and tests

* update types

Author: AnastasiiaSvietlova

package-lock.json

@@ -1,7 +1,15 @@
 {
   "name": "@bugsnag/plugin-server-session",
   "version": "8.4.0",
-  "main": "session.js",
+  "main": "dist/session.js",
+  "types": "dist/types/session.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/types/session.d.ts",
+      "default": "./dist/session.js",
+      "import": "./dist/session.mjs"
+    }
+  },
   "description": "@bugsnag/js plugin to enable session tracking in server applications",
   "homepage": "https://www.bugsnag.com/",
   "repository": {
@@ -12,7 +20,7 @@
     "access": "public"
   },
   "files": [
-    "*.js"
+    "dist"
   ],
   "author": "Bugsnag",
   "license": "MIT",
@@ -24,5 +32,11 @@
   },
   "peerDependencies": {
     "@bugsnag/core": "^8.0.0"
+  },
+  "scripts": {
+    "build": "npm run build:npm",
+    "build:npm": "rollup --config rollup.config.npm.mjs",
+    "clean": "rm -rf dist/*",
+    "test:types": "tsc -p tsconfig.json"
   }
 }

packages/plugin-server-session/package.json

@@ -0,0 +1,6 @@
+import createRollupConfig from "../../.rollup/index.mjs";
+
+export default createRollupConfig({
+  input: "src/session.ts",
+  external: ["events", "backo"],
+});

packages/plugin-server-session/rollup.config.npm.mjs

@@ -0,0 +1,19 @@
+declare module 'backo' {
+  interface BackoffOptions {
+    min?: number
+    max?: number
+    jitter?: number
+    factor?: number
+  }
+
+  class Backoff {
+    attempts: number
+    
+    constructor(options?: BackoffOptions)
+    
+    duration(): number
+    reset(): void
+  }
+
+  export = Backoff
+}

packages/plugin-server-session/src/backo.d.ts

@@ -1,10 +1,26 @@
-const { intRange, runSyncCallbacks } = require('@bugsnag/core')
-const SessionTracker = require('./tracker')
-const Backoff = require('backo')
+import { App, Client, Config, Device, Notifier, Plugin, Session, intRange, runSyncCallbacks } from '@bugsnag/core'
+import SessionTracker from './tracker'
+import Backoff from 'backo'
 
-module.exports = {
+interface PluginConfig extends Config {
+  sessionSummaryInterval?: number
+}
+
+interface SessionCount {
+  startedAt: string
+  sessionsStarted: number
+}
+
+interface SessionPayload extends Session{
+  notifier: Notifier
+  device: Device
+  app: App
+  sessionCounts: SessionCount[]
+}
+
+const plugin: Plugin<PluginConfig> = {
   load: (client) => {
-    const sessionTracker = new SessionTracker(client._config.sessionSummaryInterval)
+    const sessionTracker = new SessionTracker(client._config.sessionSummaryInterval ?? undefined)
     sessionTracker.on('summary', sendSessionSummary(client))
     sessionTracker.start()
     client._sessionDelegate = {
@@ -31,8 +47,9 @@ module.exports = {
           return client
         }
 
-        // Otherwise start a new session
-        return client.startSession()
+        // Otherwise start a new session and ensure a Client is always returned
+        const newClient = client.startSession()
+        return newClient || client
       }
     }
   },
@@ -45,7 +62,7 @@ module.exports = {
   }
 }
 
-const sendSessionSummary = client => sessionCounts => {
+const sendSessionSummary = (client: Client) => (sessionCounts: SessionCount[]): void => {
   // exit early if the current releaseStage is not enabled
   if (client._config.enabledReleaseStages !== null && !client._config.enabledReleaseStages.includes(client._config.releaseStage)) {
     client._logger.warn('Session not sent due to releaseStage/enabledReleaseStages configuration')
@@ -58,7 +75,7 @@ const sendSessionSummary = client => sessionCounts => {
   const maxAttempts = 10
   req(handleRes)
 
-  function handleRes (err) {
+  function handleRes (err?: Error | null): void {
     if (!err) {
       const sessionCount = sessionCounts.reduce((accum, s) => accum + s.sessionsStarted, 0)
       return client._logger.debug(`${sessionCount} session(s) reported`)
@@ -67,11 +84,11 @@ const sendSessionSummary = client => sessionCounts => {
       client._logger.error('Session delivery failed, max retries exceeded', err)
       return
     }
-    client._logger.debug('Session delivery failed, retry #' + (backoff.attempts + 1) + '/' + maxAttempts, err)
+    client._logger.error('Session delivery failed, retry #' + (backoff.attempts + 1) + '/' + maxAttempts, err)
     setTimeout(() => req(handleRes), backoff.duration())
   }
 
-  function req (cb) {
+  function req (cb: (err?: Error | null) => void) {
     const payload = {
       notifier: client._notifier,
       device: {},
@@ -83,7 +100,7 @@ const sendSessionSummary = client => sessionCounts => {
       sessionCounts
     }
 
-    const ignore = runSyncCallbacks(client._cbs.sp, payload, 'onSessionPayload', client._logger)
+    const ignore = runSyncCallbacks(client._cbs.sp, payload as SessionPayload, 'onSessionPayload', client._logger)
     if (ignore) {
       client._logger.debug('Session not sent due to onSessionPayload callback')
       return cb(null)
@@ -92,3 +109,5 @@ const sendSessionSummary = client => sessionCounts => {
     client._delivery.sendSession(payload, cb)
   }
 }
+
+export default plugin

packages/plugin-server-session/session.js renamed to packages/plugin-server-session/src/session.ts

@@ -1,8 +1,14 @@
+import { Session } from '@bugsnag/core'
+import EventEmitter from 'events'
+
 const DEFAULT_SUMMARY_INTERVAL = 10 * 1000
-const Emitter = require('events').EventEmitter
 
-module.exports = class SessionTracker extends Emitter {
-  constructor (intervalLength) {
+class SessionTracker extends EventEmitter {
+  private _sessions: Map<string, number>
+  private _interval: NodeJS.Timeout | null
+  private _intervalLength?: number
+
+  constructor (intervalLength?: number) {
     super()
     this._sessions = new Map()
     this._interval = null
@@ -18,19 +24,21 @@ module.exports = class SessionTracker extends Emitter {
   }
 
   stop () {
-    clearInterval(this._interval)
+    if (this._interval !== null) {
+      clearInterval(this._interval)
+    }
     this._interval = null
   }
 
-  track (session) {
+  track (session: Session) {
     const key = dateToMsKey(session.startedAt)
     const cur = this._sessions.get(key)
     this._sessions.set(key, typeof cur === 'undefined' ? 1 : cur + 1)
     return session
   }
 
   _summarize () {
-    const summary = []
+    const summary: Array<{ startedAt: string, sessionsStarted: number }> = []
     this._sessions.forEach((val, key) => {
       summary.push({ startedAt: key, sessionsStarted: val })
       this._sessions.delete(key)
@@ -40,9 +48,11 @@ module.exports = class SessionTracker extends Emitter {
   }
 }
 
-const dateToMsKey = (d) => {
+const dateToMsKey = (d: Date) => {
   const dk = new Date(d)
   dk.setSeconds(0)
   dk.setMilliseconds(0)
   return dk.toISOString()
 }
+
+export default SessionTracker

packages/plugin-server-session/tracker.js renamed to packages/plugin-server-session/src/tracker.ts

@@ -1,12 +1,11 @@
+import { Client, Session } from '@bugsnag/core'
 import { EventEmitter } from 'events'
-import { Client } from '@bugsnag/core'
-import _Tracker from '../tracker'
-import plugin from '../session'
-import { Session } from '@bugsnag/core'
+import plugin from '../src/session'
+import _Tracker from '../src/tracker'
 
 const Tracker = _Tracker as jest.MockedClass<typeof _Tracker>
 
-jest.mock('../tracker')
+jest.mock('../src/tracker')
 
 describe('plugin: server sessions', () => {
   beforeEach(() => {

packages/plugin-server-session/test/session.test.ts

@@ -1,6 +1,6 @@
-import Tracker from '../tracker'
 import { Session } from '@bugsnag/core'
 import timekeeper from 'timekeeper'
+import Tracker from '../src/tracker'
 
 describe('session tracker', () => {
   it('should track sessions and summarize per minute', done => {
@@ -28,13 +28,34 @@ describe('session tracker', () => {
   })
 
   it('should only start one interval', () => {
-    const t = new Tracker(5)
+    jest.useFakeTimers()
+    const t = new Tracker(100)
+    let summaryEmissionCount = 0
+    
+    t.track(new Session())
+    t.track(new Session())
+    
+    t.on('summary', () => {
+      summaryEmissionCount++
+    })
+
     t.start()
-    const i0 = t._interval
     t.start()
-    expect(i0).toBe(t._interval)
+    t.start()
+
+    jest.advanceTimersByTime(100)
+    expect(summaryEmissionCount).toBe(1)
+    
+    t.track(new Session())
+    jest.advanceTimersByTime(100)
+    expect(summaryEmissionCount).toBe(2)
+    
     t.stop()
-    expect(t._interval).toBe(null)
+    t.track(new Session())
+    jest.advanceTimersByTime(200)
+    expect(summaryEmissionCount).toBe(2)
+    
+    jest.useRealTimers()
   })
 
   afterEach(() => timekeeper.reset())

packages/plugin-server-session/test/tracker.test.ts

@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.json",
+  "include": ["src/**/*.ts"],
+  "compilerOptions": {
+    "lib": ["es2017"],
+    "types": ["node"]
+  }
+}

packages/plugin-server-session/tsconfig.json

@@ -21,7 +21,6 @@
     "packages/plugin-aws-lambda",
     "packages/plugin-contextualize",
     "packages/plugin-navigation-breadcrumbs",
-    "packages/plugin-server-session",
     "packages/plugin-react",
     "packages/plugin-vue",
     "packages/plugin-express",