npm install karma-eslint --save-dev

In your karma.conf.js file:

  preprocessors: {
    '**/*.js': ['eslint']
  }

Karma-eslint accepts these options:

stopOnError

• fails a test on any error default: true

errorThreshold

• a threshold value for total errors default: null
• use with stopAboveErrorThreshold to stop build if errors exceed threshold

stopAboveErrorThreshold

• stops build if errorThreshold exceeded default: false

stopOnWarning

• fails a test on any Warning default: false
• if set true, Warnings are always displayed

showWarnings

• to display Warning messages default: true
• has no effect if stopOnWarning is set true
• in such case Warnings are displayed anyway

engine

• eslint CLIEngine configuration options. default: {}

Example:

  eslint: {
    errorThreshold: 1000,
    stopAboveErrorThreshold: true,
    stopOnError: false,
    stopOnWarning: true,
    showWarnings: true,
    engine: {
      configFile: 'client/.eslintrc'
    }
  }

This plugin leverages ESLints normal configuration methods. The full list of ESLint rules are here.

For more information on Karma visit the Karma site.