in index.js [27:42]
function componentWillUpdate(nextProps, nextState) {
try {
var prevProps = this.props;
var prevState = this.state;
this.props = nextProps;
this.state = nextState;
this.__reactInternalSnapshotFlag = true;
this.__reactInternalSnapshot = this.getSnapshotBeforeUpdate(
prevProps,
prevState
);
} finally {
this.props = prevProps;
this.state = prevState;
}
}