Add guardrails to Profiler class

lib/winston/profiler.js

@@ -6,13 +6,12 @@
  */
 
 'use strict';
-
 /**
  * TODO: add class description.
  * @type {Profiler}
  * @private
  */
-module.exports = class Profiler {
+class Profiler {
   /**
    * Constructor function for the Profiler instance used by
    * `Logger.prototype.startTimer`. When done is called the timer will finish
@@ -21,12 +20,13 @@
    * @private
    */
   constructor(logger) {
-    if (!logger) {
-      throw new Error('Logger is required for profiling.');
+    const Logger = require('./logger');
+    if (typeof logger !== 'object' || Array.isArray(logger) || !(logger instanceof Logger)) {
+      throw new Error('Logger is required for profiling');
+    } else {
+      this.logger = logger;
+      this.start = Date.now();
     }
-
-    this.logger = logger;
-    this.start = Date.now();
   }
 
   /**
@@ -48,4 +48,6 @@
 
     return this.logger.write(info);
   }
 };
+
+module.exports = Profiler;

test/unit/winston/profiler.test.js

@@ -7,27 +7,27 @@
  */
 
 const assume = require('assume');
+const Logger = require('../../../lib/winston/logger');
 const Profiler = require('../../../lib/winston/profiler');
-
+const { PassThrough } = require('stream');
 describe('Profiler', function () {
   it('new Profiler()', function () {
     assume(function () {
-      var profiler = new Profiler();
-    }).throws();
+      new Profiler();
+    }).throws('Logger is required for profiling');
   });
 
   it('.done({ info })', function (done) {
-    var profiler = new Profiler({
-      write: function (info) {
-        assume(info).is.an('object');
-        assume(info.something).equals('ok');
-        assume(info.level).equals('info');
-        assume(info.durationMs).is.a('number');
-        assume(info.message).equals('testing1');
-        done();
-      }
-    });
-
+    const logger = new Logger();
+    logger.write = function (info) {
+      assume(info).is.an('object');
+      assume(info.something).equals('ok');
+      assume(info.level).equals('info');
+      assume(info.durationMs).is.a('number');
+      assume(info.message).equals('testing1');
+      done();
+    };
+    var profiler = new Profiler(logger);
     setTimeout(function () {
       profiler.done({
         something: 'ok',
@@ -36,4 +36,30 @@ describe('Profiler', function () {
       });
     }, 200);
   });
+
+  it('non logger object', function(){
+    assume(function() {
+      new Profiler(new Error('Unknown error'));
+    }).throws('Logger is required for profiling');
+
+    assume(function () {
+      new Profiler({a:'b'});
+    }).throws('Logger is required for profiling');
+
+    assume(function(){
+      new Profiler([1,2,3,4]);
+    }).throws('Logger is required for profiling');
+
+    assume(function () {
+      new Profiler(new PassThrough());
+    }).throws('Logger is required for profiling');
+
+    assume(function () {
+      new Profiler(2);
+    }).throws('Logger is required for profiling');
+
+    assume(function () {
+      new Profiler('1');
+    }).throws('Logger is required for profiling');
+  })
 });