undefined is not an object (evaluating 'hex.replace')

[wikimo]

when i run the sample, result that , how to solve it, thanks

[wikimo]

solve it myself

<AwesomeButton states={{
                        default: {
                          text: 'Press me',
                          onPress: this._login,
                          backgroundColor: '#ac0000'
                        }
                       }} />

backgroundColor is missing.