feat: logger (#64)

Fixes #63

lib/core/Logs.ts

@@ -0,0 +1,132 @@
+/**
+ * Level of logging
+ */
+export enum LogLevel {
+  DEBUG = 0,
+  INFO = 1,
+  WARN = 2,
+  ERROR = 3,
+  FATAL = 4
+}
+
+
+/**
+ * A log record. This is the data that is passed to the transports.
+ */
+export interface LogRecord {
+  level: LogLevel
+  context: string
+  message: string
+  timestamp: number
+  data?: unknown
+}
+
+
+/**
+ * A transport is a class that is responsible for actually logging the data.
+ */
+export interface LogTransport {
+  log(record: LogRecord): void
+}
+
+
+/**
+ * The LogsController is responsible for managing the transports and passing
+ * log records to them. It is a singleton.
+ */
+export class LogsController {
+  private transports: LogTransport[] = []
+
+  /**
+   * Add a transport to the controller.
+   * @param transport The transport to add
+   */
+  public register(transport: LogTransport) {
+    this.transports.push(transport)
+  }
+
+  public log(record: LogRecord) {
+    this.transports.forEach(transport => transport.log(record))
+  }
+}
+
+
+/**
+ * The Logger class is responsible for creating a log record and passing it to
+ * the LogsController.
+ */
+export class Logger {
+  /**
+   * Initialize a new logger.
+   * @param context The context of the logger. This is used to identify the source of the log.
+   */
+  constructor (
+    private context: string
+  ) {}
+
+  /**
+   * Logs a message.
+   * @param level Log level
+   * @param message Message to log
+   */
+  public log(level: LogLevel, message: string, data?: unknown) {
+    Logs.log({
+      level,
+      context: this.context,
+      message,
+      timestamp: Date.now(),
+      data
+    })
+  }
+
+  /**
+   * Debug level log.
+   * @param message Message to log
+   * @param data Data to log
+   */
+  public debug(message: string, data?: unknown) {
+    this.log(LogLevel.DEBUG, message, data)
+  }
+
+  /**
+   * Info level log.
+   * @param message Message to log
+   * @param data Data to log
+   */
+  public info(message: string, data?: unknown) {
+    this.log(LogLevel.INFO, message, data)
+  }
+
+  /**
+   * Warn level log.
+   * @param message Message to log
+   * @param data Data to log
+   */
+  public warn(message: string, data?: unknown) {
+    this.log(LogLevel.WARN, message, data)
+  }
+
+  /**
+   * Error level log.
+   * @param message Message to log
+   * @param data Data to log
+   */
+  public error(message: string, data?: unknown) {
+    this.log(LogLevel.ERROR, message, data)
+  }
+
+  /**
+   * Fatal level log.
+   * @param message Message to log
+   * @param data Data to log
+   */
+  public fatal(message: string, data?: unknown) {
+    this.log(LogLevel.FATAL, message, data)
+  }
+}
+
+
+/**
+ * The singleton instance of the LogsController.
+ */
+export const Logs = new LogsController()

lib/core/index.ts

@@ -1,2 +1,3 @@
 export * from './Result'
-export * from './Event'
+export * from './Event'
+export * from './Logs'

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@akdasa-studios/framework",
-  "version": "0.2.8",
+  "version": "0.2.9",
   "description": "Framework to build every app",
   "main": "dist/index.js",
   "typings": "dist/index.d.ts",

tests/core/Logs.spec.ts

@@ -0,0 +1,67 @@
+import { LogRecord, Logs, LogTransport, Logger, LogLevel } from '@lib/core'
+
+
+class MockTransport implements LogTransport {
+  public lastRecord: LogRecord | undefined
+  log(record: LogRecord): void {
+    this.lastRecord = record
+  }
+}
+
+
+describe('LogsController', () => {
+  describe('.register()', () => {
+    it('should register a transport', () => {
+      const transport = new MockTransport()
+      const logger = new Logger('test')
+
+      Logs.register(transport)
+      logger.log(LogLevel.DEBUG, 'message', { test: 'test' })
+
+      expect(transport.lastRecord).toBeDefined()
+      expect(transport.lastRecord?.context).toBe('test')
+      expect(transport.lastRecord?.message).toBe('message')
+      expect(transport.lastRecord?.level).toBe(LogLevel.DEBUG)
+      expect(transport.lastRecord?.timestamp).toBeDefined()
+      expect(transport.lastRecord?.data).toEqual({ test: 'test' })
+    })
+  })
+})
+
+describe('Logger', () => {
+  const transport = new MockTransport()
+  const logger = new Logger('test')
+  Logs.register(transport)
+
+  describe('.log()', () => {
+    it('log a message', () => {
+      logger.log(LogLevel.DEBUG, 'message')
+      expect(transport.lastRecord?.level).toBe(LogLevel.DEBUG)
+    })
+
+    it('debug level', () => {
+      logger.debug('message')
+      expect(transport.lastRecord?.level).toBe(LogLevel.DEBUG)
+    })
+
+    it('info level', () => {
+      logger.info('message')
+      expect(transport.lastRecord?.level).toBe(LogLevel.INFO)
+    })
+
+    it('warn level', () => {
+      logger.warn('message')
+      expect(transport.lastRecord?.level).toBe(LogLevel.WARN)
+    })
+
+    it('error level', () => {
+      logger.error('message')
+      expect(transport.lastRecord?.level).toBe(LogLevel.ERROR)
+    })
+
+    it('fatal level', () => {
+      logger.fatal('message')
+      expect(transport.lastRecord?.level).toBe(LogLevel.FATAL)
+    })
+  })
+})