React eslint error missing in props validation

You need to define propTypes as a static getter if you want it inside the class declaration:

static get propTypes() { 
    return { 
        children: PropTypes.any, 
        onClickOut: PropTypes.func 
    }; 
}

If you want to define it as an object, you need to define it outside the class, like this:

IxClickOut.propTypes = {
    children: PropTypes.any,
    onClickOut: PropTypes.func,
};

Also it’s better if you import prop types from prop-types, not react, otherwise you’ll see warnings in console (as preparation for React 16):

import PropTypes from 'prop-types';