browser versions

lib/index.js

@@ -2,7 +2,6 @@ import ReadStream from './readstream';
 import operators from './operators';
 import constants from './constats';
 import * as _ from './helpers';
-import polyfills from 'babel/polyfill';
 
 let Equation = {
   /**
@@ -151,7 +150,7 @@ const parseGroups = stack => {
   // Parantheses become inner arrays which will then be processed first
   let sub = 0;
   return stack.reduce((a, b) => {
-    if (b.includes('(')) {
+    if (b.indexOf('(') > -1) {
       if (b.length > 1) {
         _.dive(a, sub).push(b.replace('(', ''), []);
       } else {