Javascript-SDK - 4.2.0

## [4.2.0] - July 31, 2020

### New Features - Better offline support in React Native apps: - Persist downloaded datafiles in local storage for use in subsequent SDK initializations ([#430](https://github.com/optimizely/javascript-sdk/pull/430)) - Persist pending impression & conversion events in local storage ([#517](https://github.com/optimizely/javascript-sdk/pull/517), [#532](https://github.com/optimizely/javascript-sdk/pull/532))

### Bug fixes - Fixed log messages for Targeted Rollouts ([#515](https://github.com/optimizely/javascript-sdk/pull/515))

https://github.com/optimizely/javascript-sdk/releases/tag/v4.2.0