react propTypes

  propTypes: {
    // You can declare that a prop is a specific JS primitive. By default, these
    // are all optional.
    optionalArray: React.PropTypes.array,
    optionalBool: React.PropTypes.bool,
    optionalFunc: React.PropTypes.func,
    optionalNumber: React.PropTypes.number,
    optionalObject: React.PropTypes.object,
    optionalString: React.PropTypes.string,

    // Anything that can be rendered: numbers, strings, elements or an array
    // (or fragment) containing these types.
    optionalNode: React.PropTypes.node,

    // A React element.
    optionalElement: React.PropTypes.element,

    // You can also declare that a prop is an instance of a class. This uses
    // JS's instanceof operator.
    optionalMessage: React.PropTypes.instanceOf(Message),

    // You can ensure that your prop is limited to specific values by treating
    // it as an enum.
    optionalEnum: React.PropTypes.oneOf(['News', 'Photos']),

    // An object that could be one of many types
    optionalUnion: React.PropTypes.oneOfType([
      React.PropTypes.string,
      React.PropTypes.number,
      React.PropTypes.instanceOf(Message)
    ]),

    // An array of a certain type
    optionalArrayOf: React.PropTypes.arrayOf(React.PropTypes.number),

    // An object with property values of a certain type
    optionalObjectOf: React.PropTypes.objectOf(React.PropTypes.number),

    // An object taking on a particular shape
    optionalObjectWithShape: React.PropTypes.shape({
      color: React.PropTypes.string,
      fontSize: React.PropTypes.number
    }),

    // You can chain any of the above with `isRequired` to make sure a warning
    // is shown if the prop isn't provided.
    requiredFunc: React.PropTypes.func.isRequired,

    // A value of any data type
    requiredAny: React.PropTypes.any.isRequired,

    // You can also specify a custom validator. It should return an Error
    // object if the validation fails. Don't `console.warn` or throw, as this
    // won't work inside `oneOfType`.
    customProp: function(props, propName, componentName) {
      if (!/matchme/.test(props[propName])) {
        return new Error('Validation failed!');
      }
    }
  },
  /* ... */
});