diff --git a/lib/core.js b/lib/core.js
index 57b048f..671c310 100644
--- a/lib/core.js
+++ b/lib/core.js
@@ -1,7 +1,9 @@
 'use strict';
 
 var isCoreModule = require('is-core-module');
-var data = require('./core.json');
+var path = require('path');
+var fs = require('fs');
+var data = JSON.parse(String(fs.readFileSync(path.join(path.dirname(require.resolve('is-core-module/package.json')), 'core.json'))));
 
 var core = {};
 for (var mod in data) { // eslint-disable-line no-restricted-syntax