ES6 spec-compliant Object.assign shim. From https://github.com/es-shims/es6-shim
An Object.keys replacement, in case Object.keys is not available. From https://github.com/es-shims/es5-shim
Get the byte length of an ArrayBuffer, even in engines without a .byteLength method.
An ESnext spec-compliant iterator helpers shim/polyfill/replacement that works as far down as ES3.
A robust ES3-compatible polyfill for the RegExp.escape proposal - see https://github.com/tc39/proposal-regex-escaping