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optionsOrName

Either

  • An object containing further options for configuring mocking behaviour.
  • A string, which will be used as the route's name

General options​

name​

{String}

A unique string naming the route. Used to subsequently retrieve references to the calls handled by it. Only needed for advanced use cases.

response​

Instead of defining the response as the second argument of mock(), it can be passed as a property on the first argument. See the response documentation for valid values.

repeat​

{Int}

Limits the number of times the route can be used. If the route has already been called repeat times, the call to fetch() will fall through to be handled by any other routes defined (which may eventually result in an error if nothing matches it)

delay​

{Int}

Delays responding for the number of milliseconds specified.

sticky​

{Boolean}

Avoids a route being removed when reset(), restore() or resetBehavior() are called. Note - this does not preserve the history of calls to the route

sendAsJson​

{Boolean}

See global configuration

includeContentLength​

{Boolean}

See global configuration

overwriteRoutes​

{Boolean}

See global configuration

Options for defining matchers​

If multiple mocks use the same url matcher but use different options, such as headers, you will need to use the overwriteRoutes: false option.

url​

{String|RegExp}

Use any of the String or RegExp matchers described in the documentation fro the matcher parameter.

functionMatcher​

{Function}

Use a function matcher, as described in the documentation fro the matcher parameter.

method​

{String}

Match only requests using this http method. Not case-sensitive, e.g. "get", "POST"

headers​

{Object|Headers}

Match only requests that have these headers set, e.g. {"Accepts": "text/html"}

body​

{Object}

Match only requests that send a JSON body with the exact structure and properties as the one provided here.

Note that if matching on body and using Request instances in your source code, this forces fetch-mock into an asynchronous flow before it is able to route requests effectively. This means no inspection methods can be used synchronously. You must first either await the fetches to resolve, or await fetchMock.flush(). The popular library Ky uses Request instances internally, and so also triggers this mode.

e.g.{ "key1": "value1", "key2": "value2" }

matchPartialBody​

{Boolean}

Match calls that only partially match a specified body json. See global configuration for details.

query​

{Object}

Match only requests that have these query parameters set (in any order). Query parameters are matched by using Node.js querystring module. In summary the bahaviour is as follows

  • strings, numbers and booleans are coerced to strings
  • arrays of values are coerced to repetitions of the key
  • all other values, including undefined, are coerced to an empty string The request will be matched whichever order keys appear in the query string. Any query parameters sent in the request which are not included in the keys of the object provided will be ignored.

Examples​

  • {"q": "cute+kittenz"} ?q=cute kittenz or ?q=cute+kittenz or ?q=cute+kittenz&mode=big
  • {"tags": ["cute", "kittenz"]} ?tags=cute&tags=kittenz
  • {"q": undefined, inform: true} ?q=&inform=true

params​

{Object}

When the express: keyword is used in a string matcher, match only requests with these express parameters e.g {"section": "feed", "user": "geoff"}