Radium.js

this.props.Stroke.colors.map((el, id) => (
        <li key={id} >
            <div className="colorBox" onClick={() => {this.cancelColor(id)}}
                style= {{
                    background: el,
                    color: (() => (tinycolor(el).isDark() ? 'white' : 'black'))()
                }}>
                <p>{el}</p>
            </div>
        </li>
    )
)