diff --git a/index.js b/index.js
index c043357..e29b290 100644
--- a/index.js
+++ b/index.js
@@ -2,6 +2,7 @@
 var escapeStringRegexp = require('escape-string-regexp');
 var ansiStyles = require('ansi-styles');
 var supportsColor = require('supports-color');
+var forkeys = require('forkeys-compat');
 var defineProps = Object.defineProperties;
 var isSimpleWindowsTerm = process.platform === 'win32' && !/^xterm/i.test(process.env.TERM);
 
@@ -17,7 +18,7 @@ if (isSimpleWindowsTerm) {
 
 var styles = {};
 
-Object.keys(ansiStyles).forEach(function (key) {
+forkeys(ansiStyles, function (key) {
 	ansiStyles[key].closeRe = new RegExp(escapeStringRegexp(ansiStyles[key].close), 'g');
 
 	styles[key] = {