import PropTypes from 'prop-types'; class CharacterCounter extends React.PureComponent { checkRemainingText (diff) { if (diff <= 0) { return {diff}; } return {diff}; } render () { const diff = this.props.max - this.props.text.replace(/[\uD800-\uDBFF][\uDC00-\uDFFF]/g, "_").length; return this.checkRemainingText(diff); } } CharacterCounter.propTypes = { text: PropTypes.string.isRequired, max: PropTypes.number.isRequired } export default CharacterCounter;