The files array determines which files are included in the browser, watched, and served by Karma.

files #

Type. Array No Default. This property is mandatory. Description. Each item is either a string (equivalent to { pattern: "<string>" }) or an object with the following properties:

pattern #

  • Type. String
  • No Default. This property is mandatory.
  • Description. The pattern to use for matching. See below for details on how patterns are resolved.

type #

  • Type. String
  • Default. Will attempt to determine type based on file extension. If that fails, defaults to js.
  • Possible Values:
    • css - Include using <link rel="stylesheet"> tag.
    • html - Include using HTML Imports. Note that this feature is obsolete and does not work in the modern browsers.
    • js - Include using <script></script> tag.
    • module - Include using <script type="module"></script> tag.
    • dom - Inline content of the file in the page. This can be used, for example, to test components combining HTML and JS.
  • Description. The type determines the mechanism for including the file.

watched #

  • Type. Boolean
  • Default. true
  • Description. If autoWatch is true all files that have set watched to true will be watched for changes.

included #

  • Type. Boolean

  • Default. true

  • Description. Should the files be included in the browser using <script> tag? Use false if you want to load them manually, eg. using Require.js.

    If a file is covered by multiple patterns with different include properties, the most specific pattern takes precedence over the other.

    The specificity of the pattern is defined as a six-tuple, where larger tuple implies lesser specificity: (nglob parts, nglob star, nstar, next glob, nrange, noptional). Tuples are compared lexicographically.

    The nglob parts is the number of patterns after the bracket sections are expanded. E.g. the the pattern {0...9} will yield nglob parts=10. The rest of the tuple is decided as the least specific of each expanded pattern.

served #

  • Type. Boolean
  • Default. true
  • Description. Should the files be served by Karma's webserver?

nocache #

  • Type. Boolean
  • Default. false
  • Description. Should the files be served from disk on each request by Karma's webserver?

integrity #

  • Type. String
  • Default. undefined
  • Description. Set the integrity HTML attribute value to the <script> or the <link> tag loading the resource that matches the given pattern if the pattern is an absolute URL.

Pattern matching and basePath #

  • All of the relative patterns will get resolved using the basePath first.
  • If the basePath is a relative path, it gets resolved to the directory where the configuration file is located.
  • Eventually, all the patterns will get resolved into files using glob, so you can use minimatch expressions like test/unit/**/*.spec.js.

Ordering #

  • The order of patterns determines the order in which files are included in the browser.
  • Multiple files matching a single pattern are sorted alphabetically.
  • Each file is included exactly once. If multiple patterns match the same file, it's included as if it only matched the first pattern.

Preprocessor transformations #

Depending on preprocessor configuration, be aware that files loaded may be transformed and no longer available in their native format. For instance, if html2js preprocessor is enabled, the actual .html files are no longer served - but rather available as window.__html__['my.html']. Read more about preprocessors.

Complete example #

Here is a complete example showing the different options possible:

files: [

  // Detailed pattern to include a file. Similarly other options can be used
  { pattern: 'lib/angular.js', watched: false },
  // Prefer to have watched false for library files. No need to watch them for changes

  // simple pattern to load the needed testfiles
  // equal to {pattern: 'test/unit/*.spec.js', watched: true, served: true, included: true}

  // this file gets served but will be ignored by the watcher
  // note if html2js preprocessor is active, reference as `window.__html__['compiled/index.html']`
  {pattern: 'compiled/index.html', watched: false},

  // this file only gets watched and is otherwise ignored
  {pattern: 'app/index.html', included: false, served: false},

  // this file will be served on demand from disk and will be ignored by the watcher
  {pattern: 'compiled/', included: false, served: true, watched: false, nocache: true}

Loading files from another server #

Pattern can also be an absolute URL. This allows including files which are not served by Karma.


  files: [
    { pattern: '', type: 'js' }

Absolute URLs have some special rules comparing to the regular file paths:

  • Globing is not support, so each URL must be specified as a separate pattern.
  • Most of the regular options are not supported:
    • watched is always false
    • included is always true
    • served is always false
    • nocache is always false

Loading Assets #

By default all assets are served at http://localhost:[PORT]/base/

Example for loading images

files: [
  {pattern: 'test/images/*.jpg', watched: false, included: false, served: true, nocache: false}

The pattern is a glob which matches the specified image assets. Watched and included are not necessary as images are not tests. However, they will need to be served to the browser.

In this case an image would be accessed at http://localhost:[PORT]/base/test/images/[MY IMAGE].jpg

Notice the base in the URL, it is a reference to your basePath. You do not need to replace or provide your own base.

In addition, you can use a proxy

proxies: {
  "/img/": "http://localhost:8080/base/test/images/"

Now you can fetch images in test/images at http://localhost:8080/img/[MY IMAGE].jpg

Change 8080 to the port you use

You can also use proxies without specifying the protocol, hostname, and port

proxies: {
  "/img/": "/base/test/images/"

Webserver features #

  • Range requests.
  • In-memory caching of files.
  • Watching for updates in the files.
  • Proxies to alter file paths.
  • Support for custom middlewares (the middleware configuration option).