fix(browser): filter browser logging by level

Do not log lower levels if `browserConsoleLogOptions.level` is set

Fixes  #2228

docs/dev/04-public-api.md

@@ -136,7 +136,7 @@ stopper.stop({port: 9876}, function(exitCode) {
 
 ## karma.config.parseConfig([configFilePath], [cliOptions])
 
-This function will load given config file and returns a filled config object. 
+This function will load given config file and returns a filled config object.
 This can be useful if you want to integrate karma into another tool and want to load
 the karma config while honoring the karma defaults. For example, the [stryker-karma-runner](https://github.com/stryker-mutator/stryker-karma-runner)
 uses this to load your karma configuration and use that in the stryker configuration.
@@ -145,7 +145,7 @@ uses this to load your karma configuration and use that in the stryker configura
 const cfg = require('karma').config;
 const path = require('path');
 // Read karma.conf.js, but override port with 1337
-const karmaConfig = cfg.parseConfig(path.resolve('./karma.conf.js'), { port: 1337 } ); 
+const karmaConfig = cfg.parseConfig(path.resolve('./karma.conf.js'), { port: 1337 } );
 ```
 
 ## karma.constants
@@ -182,6 +182,10 @@ The value for the log `info` level
 
 The value for the log `debug` level
 
+### **constants.LOG_PRIORITIES**
+
+An array of log levels in descending order, i.e. `LOG_DISABLE`, `LOG_ERROR`, `LOG_WARN`, `LOG_INFO`, and `LOG_DEBUG`
+
 ### **constants.COLOR_PATTERN**
 
 The default color pattern for log output

lib/constants.js

@@ -15,6 +15,14 @@ exports.LOG_ERROR = 'ERROR'
 exports.LOG_WARN = 'WARN'
 exports.LOG_INFO = 'INFO'
 exports.LOG_DEBUG = 'DEBUG'
+exports.LOG_PRIORITIES = [
+  exports.LOG_DISABLE,
+  exports.LOG_ERROR,
+  exports.LOG_WARN,
+  exports.LOG_INFO,
+  exports.LOG_DEBUG,
+  exports.LOG_DISABLE
+]
 
 // Default patterns for the pattern layout.
 exports.COLOR_PATTERN = '%[%d{DATE}:%p [%c]: %]%m'

lib/reporters/base.js

@@ -1,5 +1,6 @@
 var util = require('util')
 
+var constants = require('../constants')
 var helper = require('../helper')
 
 var BaseReporter = function (formatError, reportSlow, useColors, browserConsoleLogOptions, adapter) {
@@ -65,14 +66,19 @@ var BaseReporter = function (formatError, reportSlow, useColors, browserConsoleL
 
   this.onBrowserLog = function (browser, log, type) {
     if (!browserConsoleLogOptions || !browserConsoleLogOptions.terminal) return
+    type = type.toUpperCase()
+    if (browserConsoleLogOptions.level) {
+      var logPriority = constants.LOG_PRIORITIES.indexOf(browserConsoleLogOptions.level.toUpperCase())
+      if (constants.LOG_PRIORITIES.indexOf(type) > logPriority) return
+    }
     if (!helper.isString(log)) {
       // TODO(vojta): change util to new syntax (config object)
       log = util.inspect(log, false, undefined, this.USE_COLORS)
     }
     if (this._browsers && this._browsers.length === 1) {
-      this.writeCommonMsg(util.format(this.LOG_SINGLE_BROWSER, type.toUpperCase(), log))
+      this.writeCommonMsg(util.format(this.LOG_SINGLE_BROWSER, type, log))
     } else {
-      this.writeCommonMsg(util.format(this.LOG_MULTI_BROWSER, browser, type.toUpperCase(), log))
+      this.writeCommonMsg(util.format(this.LOG_MULTI_BROWSER, browser, type, log))
     }
   }
 

test/unit/reporters/base.spec.js

@@ -83,6 +83,18 @@ describe('reporter', function () {
       return expect(writeSpy).to.have.been.calledWith('LOG: Message\n')
     })
 
+    it('should not log if lower priority than browserConsoleLogOptions.level', function () {
+      var reporter = new m.BaseReporter(null, null, true, {
+        browserConsoleLogOptions: {level: 'ERROR'}
+      }, adapter)
+      var writeSpy = sinon.spy(reporter, 'writeCommonMsg')
+
+      reporter._browsers = ['Chrome']
+      reporter.onBrowserLog('Chrome', 'Message', 'LOG')
+
+      return writeSpy.should.have.not.been.called
+    })
+
     return it('should format log messages correctly for multi browsers', function () {
       var writeSpy = sinon.spy(reporter, 'writeCommonMsg')