Change from React 0.12 to 0.13

React 0.13 brings several changes, one of which affects tween-state in a subtle way.

Previously, setState might or might not have been synchronous. Under 0.12:

// assume initial state of {a: 0}
this.setState({a: 10});
this.tweenState('a', {endValue: 20});

The expectation is that tweenState correctly deduce the beginValue of 10. It did: it read into the component's internal _pendingState if there is any, and used that as the beginValue. Though you really shouldn't have had that expectation. The correct way would be this.setState({a: 10}, () => this.tweenState('a', {endValue: 20})).

Same category, but more relevant example:

// assume initial state of {a: 0}
this.tweenState('a', {endValue: 10});
this.tweenState('a', {endValue: 20}); // why are you doing this though

Under React 0.12: from 0 to 20 (tween-state <= 0.0.5).

Under React 0.13: from 10 to 20 (tween-state >= 1.0.1).