Module `assert` does not exist

Hey,
I am using eosjs-keygen for generating EOS key, in my React and React-Native app. Key-pairs are generated successfully in React, but when I tried same thing on React-Native, it causes following issue :

> Error: Unable to resolve module `assert` from `/home/Desktop/React-Native/project/node_modules/eosjs-keygen/lib/keystore.js`: Module `assert` does not exist in the Haste module map.