nock/dist/lib/interceptors/builtin.js

HTTP server mocking and expectations library for Node.js

import * as common from '../common.js'
import handleRequest from '../handle-request.js'
import { setGetRequestBody } from '../utils/node/index.js'
import { BatchInterceptor } from '@mswjs/interceptors'
import { FetchInterceptor } from '@mswjs/interceptors/fetch'
import { HttpRequestInterceptor } from '@mswjs/interceptors/http'

const interceptor = new BatchInterceptor({
  name: 'intercept',
  interceptors: [new HttpRequestInterceptor(), new FetchInterceptor()],
})

function activate() {
  interceptor.apply()

  // Force msw to forward Nock's error instead of coerce it into 500 error
  interceptor.on('unhandledException', ({ controller, error }     ) => {
    controller.errorWith(error)
  })
  interceptor.on(
    'request',
    async function ({ request, controller, initiator }) {
      if (request.headers.get('expect') === '100-continue') {
        // We currently do not support mocking 100-continue responses, so they are passed through for now.
        return
      }

      // If this is GET request with body, we need to read the body from the socket because Fetch API doesn't support this.
      const requestBodyBuffer              = common.decompressRequestBody(
        await request.clone().arrayBuffer(),
        request.headers.get('content-encoding') || '',
      )               

      const decompressedRequest = new Request(request, {
        body:
          requestBodyBuffer.byteLength > 0 && request.method !== 'GET'
            ? requestBodyBuffer
            : undefined,
      })
      if (requestBodyBuffer.byteLength > 0 && request.method === 'GET') {
        setGetRequestBody(decompressedRequest, requestBodyBuffer)
      }

      const response = await handleRequest(decompressedRequest)
      if (response) {
        controller.respondWith(response)
      }
    },
  )
}

function deactivate() {
  interceptor.dispose()
}

export { activate, deactivate }