Passing Proptypes.shape to Proptypes.arrayOf in react

In your code:

let City = PropTypes.shape({  name: React.PropTypes.string,  population: PropTypes.number}); 

What version of React are you using? You're referencing PropTypes from React.PropTypes and PropTypes. How are you importing PropTypes? Are you using the prop-types package?

I am using a similar scenario and it works for me. What does your render look like and what is the data provided for the prop?

For me, the following absolutely works:

cities: PropTypes.arrayOf(City)

I've got the same issue, and on my case, it was because one file was loaded before the other file.

In your case, it could be because City.js is not yet loaded when you load State.js

I can share what was the problem in my case. This was the code that caused the error:

const answerPropType = PropTypes.shape({    author: PropTypes.string.isRequired,    text: PropTypes.string.isRequired,    followUps: PropTypes.arrayOf(followUpPropType)})const followUpPropType = PropTypes.shape({    author: PropTypes.string.isRequired,    text: PropTypes.string.isRequired})

The problem is that followUpPropType was declared after answerPropType. So I just inverted their order:

const followUpPropType = PropTypes.shape({    author: PropTypes.string.isRequired,    text: PropTypes.string.isRequired})const answerPropType = PropTypes.shape({    author: PropTypes.string.isRequired,    text: PropTypes.string.isRequired,    followUps: PropTypes.arrayOf(followUpPropType)})