How to use the apollo-link-http-common.serializeFetchParameter function in apollo-link-http-common

if (body.variables) {
    let serializedVariables;
    try {
      serializedVariables = serializeFetchParameter(
        body.variables,
        'Variables map',
      );
    } catch (parseError) {
      return { parseError };
    }
    addQueryParam('variables', serializedVariables);
  }
  if (body.extensions) {
    let serializedExtensions;
    try {
      serializedExtensions = serializeFetchParameter(
        body.extensions,
        'Extensions map',
      );
    } catch (parseError) {
      return { parseError };
    }
    addQueryParam('extensions', serializedExtensions);
  }

  // Reconstruct the URI with added query params.
  // XXX This assumes that the URI is well-formed and that it doesn't
  //     already contain any of these query params. We could instead use the
  //     URL API and take a polyfill (whatwg-url@6) for older browsers that
  //     don't support URLSearchParams. Note that some browsers (and
  //     versions of whatwg-url) support URL but not URLSearchParams!
  let fragment = '',

// the extra level of JSON serialization!
  const queryParams = [];
  const addQueryParam = (key: string, value: string) => {
    queryParams.push(`${key}=${encodeURIComponent(value)}`);
  };

  if ('query' in body) {
    addQueryParam('query', body.query);
  }
  if (body.operationName) {
    addQueryParam('operationName', body.operationName);
  }
  if (body.variables) {
    let serializedVariables;
    try {
      serializedVariables = serializeFetchParameter(
        body.variables,
        'Variables map',
      );
    } catch (parseError) {
      return { parseError };
    }
    addQueryParam('variables', serializedVariables);
  }
  if (body.extensions) {
    let serializedExtensions;
    try {
      serializedExtensions = serializeFetchParameter(
        body.extensions,
        'Extensions map',
      );
    } catch (parseError) {

contextConfig,
        ),
      );

      const loadedBody = optsAndBody.map(({ body }) => body);
      const options = optsAndBody[0].options;

      // There's no spec for using GET with batches.
      if (options.method === 'GET') {
        return fromError(
          new Error('apollo-link-batch-http does not support GET requests'),
        );
      }

      try {
        (options as any).body = serializeFetchParameter(loadedBody, 'Payload');
      } catch (parseError) {
        return fromError(parseError);
      }

      let controller;
      if (!(options as any).signal) {
        const { controller: _controller, signal } = createSignalIfSupported();
        controller = _controller;
        if (controller) (options as any).signal = signal;
      }

      return new Observable(observer => {
        fetcher(chosenURI, options)
          .then(response => {
            // Make the raw response available in the context.
            operations.forEach(operation => operation.setContext({ response }));

// Client awareness headers are context overridable.
        ...(name && { 'apollographql-client-name': name }),
        ...(version && { 'apollographql-client-version': version }),
        ...headers
      }
    }

    const { options, body } = selectHttpOptionsAndBody(
      operation,
      fallbackHttpConfig,
      linkConfig,
      contextConfig
    )

    const { clone, files } = extractFiles(body)
    const payload = serializeFetchParameter(clone, 'Payload')

    if (files.size) {
      // Automatically set by fetch when the body is a FormData instance.
      delete options.headers['content-type']

      // GraphQL multipart request spec:
      // https://github.com/jaydenseric/graphql-multipart-request-spec

      const form = new FormData()

      form.append('operations', payload)

      const map = {}
      let i = 0
      files.forEach(paths => {
        map[++i] = paths

if (
      useGETForQueries &&
      !operation.query.definitions.some(definitionIsMutation)
    ) {
      options.method = 'GET';
    }

    if (options.method === 'GET') {
      const { newURI, parseError } = rewriteURIForGET(chosenURI, body);
      if (parseError) {
        return fromError(parseError);
      }
      chosenURI = newURI;
    } else {
      try {
        (options as any).body = serializeFetchParameter(body, 'Payload');
      } catch (parseError) {
        return fromError(parseError);
      }
    }

    return new Observable(observer => {
      fetcher(chosenURI, options)
        .then(response => {
          operation.setContext({ response });
          return response;
        })
        .then(parseAndCheckHttpResponse(operation))
        .then(result => {
          // we have data and can send it to back up the link chain
          observer.next(result);
          observer.complete();