app/ItemView/PriorityFormatter.jsx

import React from "react";
import PropTypes from "prop-types";

class PriorityFormatter extends React.Component {
  static propTypes = {
    priority: PropTypes.string.isRequired,
  };

  returnPriority(priority) {
    if (typeof priority !== "undefined" || priority != null) {
      return priority.replace(/\w\S*/g, function (txt) {
        return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();
      });
    } else {
      return "Unknown";
    }
  }

  render() {
    return <div>{this.returnPriority(this.props.priority)}</div>;
  }
}

export default PriorityFormatter;