React mixin that warns if a propTypes key is missing

gistfile1.js

define('validation', [], function() {

    return {
        allPropsSpecifiedMixing: {
            componentDidMount: function() {
                var unspecifiedPropKeys = _.difference(
                    _.keys(this.props),
                    _.keys(this.type.propTypes || {}).concat('ref'));
                if (unspecifiedPropKeys.length) {
                    console.warn('Component ' +
                        (this.type.displayName || '?') +
                        ' missing propType values for: ' +
                        JSON.stringify(unspecifiedPropKeys));
                }
            }
        }
    };

});