.

package.json

@@ -61,9 +61,9 @@
     "prettier": "^1.14.3",
     "promise-timeout": "^1.3.0",
     "promisify-event": "^1.0.0",
+    "promisify-function": "^1.3.2",
     "request": "^2.88.2",
     "sauce-connect-launcher": "^1.2.4",
-    "util.promisify": "^1.0.1",
     "webpack": "^4.43.0",
     "webpack-stream": "^5.2.1"
   },

tests/browsers/tests.js

@@ -1,7 +1,7 @@
 /* eslint-disable import/no-extraneous-dependencies */
 import feedmeClient from "feedme-client/bundle"; // Avoid source-map-support warning
 import promisifyEvent from "promisify-event";
-import promisify from "util.promisify";
+import promisify from "promisify-function"; // Node's util.promisify and other major promisification packages do not transpily/polyfill properly
 import { timeout as promiseTimeout } from "promise-timeout";
 
 // Included using <script> tags in index.html

tests/node/client.test.js

@@ -1,7 +1,7 @@
 import WebSocket from "ws";
 import promisifyEvent from "promisify-event";
 import delay from "delay";
-import promisify from "util.promisify"; // Need to be able to run build tests in Node 6
+import promisify from "promisify-function"; // Need to be able to run build tests in Node 6
 import transportWsClient from "../../build/client";
 
 /*

tests/node/server.test.js

@@ -2,7 +2,7 @@ import WebSocket from "ws";
 import http from "http";
 import request from "request";
 import check from "check-types";
-import promisify from "util.promisify"; // Need to be able to run build tests in Node 6
+import promisify from "promisify-function"; // Need to be able to run build tests in Node 6
 import promisifyEvent from "promisify-event";
 import delay from "delay";
 import transportWsServer from "../../build/server";