Data Mocks Server

This package was originally a port of https://github.com/ovotech/data-mocks that prefers spinning up an express server instead of mocking out fetch and XHR operations. Thanks goes to grug for his idea and implementation.

Table of contents

• Data Mocks Server
  • Table of contents
  • Installation
  • Example usage
  • API
    • run
      • default
      • scenarios
      • options
  • Types
    • Mock
    • HttpMock
    • Response
    • HttpResponseFunction
    • GraphQlMock
      • Operation
    • GraphQlResponse
    • GraphQlResponseFunction
    • Override

Installation

npm install data-mocks-server

Example usage

const { run } = require('data-mocks-server');

run({
  default: [
    {
      url: '/api/test-me',
      method: 'GET',
      response: { data: { blue: 'yoyo' } },
    },
  ],
  scenarios: {
    cheese: [
      {
        url: '/api/test-me',
        method: 'GET',
        response: { data: { blue: 'cheese' } },
      },
    ],
  },
});

Calls to http://localhost:3000/api/test-me will start by returning { blue: 'yoyo' }.

Visiting http://localhost:3000 will allow you to Modify scenarios. The default response will always be included unless a scenario overrides it. In this case enabling cheese will modify /api/test-me so that it returns { blue: 'cheese' }.

API

createExpressApp

Returns the internal express instance

function({ default, scenarios, options })

run

Returns an http server, with an additional kill method

function({ default, scenarios, options })

default

Array<Mock> | { context, mocks } | required

scenarios

{ [scenarioName]: Array<Mock> | { group, mocks } }

options

{ port, uiPath, modifyScenariosPath, resetScenariosPath, scenariosPath } | defaults to {}

Types

Mock

HttpMock | GraphQlMock

See HttpMock and GraphQlMock for more details.

HttpMock

{ url, method, response }

Response

{ status, headers, data, delay }

HttpResponseFunction

function({ query, body, params, context, updateContext }): response | Promise<response>

GraphQlMock

{ url, method, operations }

Operation

{ type, name, response }

GraphQlResponse

{ status, headers, data, delay }

GraphQlResponseFunction

function({ variables, context, updateContext }): response | Promise<response>

Allowing for multiple responses

Sometimes you may want an endpoint to respond with different status codes depending on what is sent. It is the recommendation of this package that this can be achieved by using scenarios. However, given response can be a function, it is possible to respond with a different value for the status, headers, data and delay properties:

const mock = {
  url: '/some-url',
  method: 'GET',
  response: ({ body }) => {
    if (body.name === 'error1') {
      return {
        status: 400,
        data: { message: 'something went wrong' },
        delay: 1000,
      };
    }

    if (body.name === 'error2') {
      return {
        status: 500,
        data: { message: 'something else went wrong' },
        delay: 2000,
      };
    }

    if (body.name === 'notFound') {
      return {
        status: 404,
        data: { message: 'no data here' },
      };
    }

    // Default status is 200
    return { data: { message: 'success' } };
  },
};