[BUG]: execute link gives an error in 3.7.0

Intended outcome:

I use this function to execute an introspection query to my GraphQL server.

import { execute, HttpLink, toPromise, gql } from "@apollo/client";
import { get, map, filter, pick, isFunction } from "lodash";
import { getIntrospectionQuery, buildClientSchema, introspectionFromSchema } from "graphql";

/**
 * Function that executes a query to get our schemas.
 * For details see: https://www.apollographql.com/docs/resources/graphql-glossary/#introspection
 *
 * @param {Function} - callback function to execute when query resolves.
 * @param callback
 */
async function introspectionQuery (callback) {
	const link = new HttpLink({ uri: process.env.GRAPHQL_URL });

	console.log("introspectionQuery called", process.env.GRAPHQL_URL);

	// For single execution operations, a Promise can be used
	await toPromise(execute(link, {
		query: gql(getIntrospectionQuery()),
	})).then(({ data }) => {
		console.log("introspectionQuery executed", data);

		// store information about schema types to be used with IntrospectionFragmentMatcher
		global.fragmentTypes = {
			__schema: {
				types: map(filter(get(data, "__schema.types", []), type => type.possibleTypes !== null), type => pick(type, ["kind", "name", "possibleTypes"])),
			},
		};

		// store stringified version of schema types to send to client
		global.unionsInterfaceTypes = JSON.stringify(global.fragmentTypes).replace(/</g, "\\u003c");

		// build and store schemas to be used with bridge for uniforms library
		global.schema = buildClientSchema(data);

		// store stringified version of schemas to send to client
		global.schemaString = JSON.stringify(get(data, "__schema", {})).replace(/</g, "\\u003c");
	}).catch(error => console.log(`introspectionQuery received error ${error}`));

	// execute callback
	if (isFunction(callback)) callback();
}

Using @apollo/client@3.6.9 this works as intended and returns me the result of the query.

Actual outcome:

Using @apollo/client@3.7.0 this does not work anymore and returns the following error:

TypeError: headers.hasOwnProperty is not a function

How to reproduce the issue:

I don’t have a working repo right now, but if required I can make one.

Versions

Working version

System:
    OS: Linux 4.15 Ubuntu 18.04.1 LTS (Bionic Beaver)
  Binaries:
    Node: 14.18.1 - ~/.nvm/versions/node/v14.18.1/bin/node
    npm: 6.14.15 - ~/.nvm/versions/node/v14.18.1/bin/npm
  npmPackages:
    @apollo/client: ^3.6.9 => 3.6.9 

Failing version

System:
    OS: Linux 4.15 Ubuntu 18.04.1 LTS (Bionic Beaver)
  Binaries:
    Node: 14.18.1 - ~/.nvm/versions/node/v14.18.1/bin/node
    npm: 6.14.15 - ~/.nvm/versions/node/v14.18.1/bin/npm
  npmPackages:
    @apollo/client: ^3.7.0 => 3.7.0 

[leepowellnbs]

@simplecommerce Thanks for the update, seems we too were using an old version of isomorphic-fetch as a polyfill for our jest tests, upgrading to the latest version has fixed it!

[simplecommerce]

Ok I figured out my problem, my project runs Meteor and I was using isomorphic-fetch@2.2.1. I installed the latest version 3.0.0 and it works!