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Pretender

Pretender is a javascript library for the browser that intercepts network requests made with fetch or XMLHttpRequest. It has a straight-forward syntax for defining routes. Unlike mock service worker, which relies on service workers, pretender patches globals in order to capture requests made. This makes pretender quicker to setup than msw but sacrifices amongst other benefits; being able to see the intercepted requests in the network tab of browser developer tools. Captured network requests from pretender can be logged however (see below).

Installation​

# npm
npm install --save-dev nock @graphql-mocks/network-pretender

# yarn
yarn add --dev nock @graphql-mocks/network-pretender

Usage​

import Pretender from 'pretender';
import { pretenderHandler } from '@graphql-mocks/network-pretender';
import graphqlSchema from './graphql-schema';
import { GraphQLHandler } from 'graphql-mocks';

// create or import GraphQLHandler
const graphqlHandler = new GraphQLHandler({
  dependencies: { graphqlSchema }
});

// create Pretender instance
const server = new Pretender(function () {
  // specify route or url to intercept with created handler via `pretenderHandler`
  this.post('http://graphql-api.com/graphql', pretenderHandler(graphqlHandler));
});

Logging Intercepted Requests​

While there isn't the network tab to check there is logging that can be added to captured requests that can help with debugging.

const server = new Pretender(function () {
  this.post('http://graphql-api.com/graphql', pretenderHandler(graphqlHandler));
});

server.handledRequest = function (verb, path, request) {
  console.log(`[${verb}] @ ${path}`);
  console.log({ request });
};

Resolver Context​

The pretender request object is made available within the resolver context under the pretender property:

function resolver(parent, args, context, info) {
  const { pretender } = context;

  // reference to the Pretender request object
  pretender.req;
}

API Documentation​

See the API Documentation for types and more details.