init

lib/conversion.js

@@ -0,0 +1,48 @@
+/** properHex 
+ * 
+ * @param {string} val original value
+ * 
+ * @returns {{hex: Array<number>, str: string}}
+*/
+let properHex = (val) => {
+  let retval = {
+    hex: [],
+    str: ""
+  };
+  if (Buffer.isBuffer(val)) 
+  {
+    retval.str = val.toString('hex').toUpperCase().replace(/([0-9A-F]{2})/g, '$1 ');
+    retval.str = "[ " + retval.str.substring(0, retval.str.length - 1) + " ]";
+    retval.hex = val;
+    return retval;
+  }
+  if (typeof val === 'string')
+  {
+    let b = Buffer.from(val);
+    return properHex(b);
+  }
+}
+
+/** dictionaryConversion
+ * 
+ * @param {string} origin 
+ * @param {Map} dict 
+ * 
+ * @returns {string}
+ * 
+ */
+let dictionaryConversion = (origin, dict) => {
+  let retval = "";
+  dict.forEach((v, k, m) => {
+    // if k is found in origin replace it with v
+    if (origin.indexOf(k) > -1) {
+      retval = origin.replace(k, v);
+    }
+  });
+  return retval;
+}
+
+module.exports = {
+  properHex,
+  dictionaryConversion
+}

lib/logging.js

@@ -0,0 +1,104 @@
+const conversion = require("./conversion");
+
+class Logger {
+  /** Logger
+   * 
+   * @param {{
+   * output: NodeJS.WritableStream, 
+   * template: string, 
+   * argsPlaceholder: string, 
+   * historySize: number, 
+   * defaultLevel: string
+   * }} options
+   */
+  constructor(options = {})
+  {
+    this.output = options.output || process.stdout;
+    this.template = options.template || "[{level} {timestamp}] {message}";
+    this.levelsColors = { // no same colors
+      debug: "\x1b[32m",
+      info:  "\x1b[36m",
+      warn:  "\x1b[33m",
+      error: "\x1b[31m",
+      fatal: "\x1b[35m"
+    };
+    this.dict = options.dict || null;
+    this.argsPlaceholder = options.argsPlaceholder || "{}";
+    this.defaultLevel = options.defaultLevel || "info";
+    this.history = [];
+    this.historySize = options.historySize || 100;
+    this.onHistoryFull = options.onHistoryFull || function() {
+      // TODO: implement
+    };
+  }
+
+  /** log 
+   * 
+   * @param {string} message
+   * @param {any} ...args
+   * 
+   */
+  log (message, ...args)
+  {
+    this.alog(this.defaultLevel, message, ...args);
+  }
+
+  /** alog 
+   * 
+   * @param {string} level
+   * @param {string} message
+   * @param {any} ...args
+   * 
+   */
+  alog(level, message, ...args)
+  {
+    //replace placeholders with args
+    let msg = this.template;
+
+    msg = msg.replace(/\{timestamp\}/g, new Date().toISOString());
+    msg = msg.replace(/\{level\}/g, level.charAt(0).toUpperCase());
+    msg = msg.replace(/\{message\}/g, message);
+
+    //replace placeholders with args
+    let argPlaceholder = this.argsPlaceholder;
+    let regex = new RegExp(argPlaceholder, "g");
+    let stringArgCount = (regex.exec(msg) || []).length;
+    args.forEach((v, i, a) => {
+      if (Buffer.isBuffer(v))
+      {
+        v = conversion.properHex(v).str;
+      }
+      if (typeof v === 'object')
+      {
+        v = JSON.stringify(v);
+      }
+
+      msg = msg.replace(argPlaceholder, v);
+    });
+    if (stringArgCount < args.length)
+      msg += ` (${args.length - stringArgCount} args overflow.)`;
+    else if (stringArgCount > args.length)
+      msg += ` (${stringArgCount - args.length} args missing.)`;
+
+    //replace dictionary keys
+    if (this.dict)
+      msg = dictionaryConversion(msg, this.dict);
+
+    // add color
+    msg = this.levelsColors[level] + msg + "\x1b[0m";
+
+    //log
+    this.output.write(msg + "\n");
+
+    //save to history
+    this.history.push({
+      level: level,
+      message: message,
+      args: args
+    });
+    if (this.history.length >= this.historySize)
+      this.onHistoryFull();
+  }
+}
+
+module.exports = Logger;