![javascript - Undefined is not an object (evaluating 'React.PropTypes.Number') error - Stack Overflow javascript - Undefined is not an object (evaluating 'React.PropTypes.Number') error - Stack Overflow](https://i.stack.imgur.com/9okLC.png)
javascript - Undefined is not an object (evaluating 'React.PropTypes.Number') error - Stack Overflow
undefined is not an ovject (evaluating '_react.PropTypes.string') · Issue #2009 · aksonov/react-native-router-flux · GitHub
Kent C. Dodds 🌌 on X: "Are you using PropTypes because you're unable to use TypeScript/Flow and worried that you can't use PropTypes for custom hooks? Well check this out! Using https://t.co/ejkvbCjpTz
undefined is not an object evaluating ReactPropTypes.string · Issue #14590 · facebook/react-native · GitHub
![How TypeScript helps us prevent the most common error in JavaScript development | by Kevin Gelpes | Medium How TypeScript helps us prevent the most common error in JavaScript development | by Kevin Gelpes | Medium](https://miro.medium.com/v2/resize:fit:818/1*MNvsifPzXkS57rKwvDHQMw.png)
How TypeScript helps us prevent the most common error in JavaScript development | by Kevin Gelpes | Medium
![Cannot read property 'string' of undefined · Issue #2517 · aksonov/react-native-router-flux · GitHub Cannot read property 'string' of undefined · Issue #2517 · aksonov/react-native-router-flux · GitHub](https://user-images.githubusercontent.com/11005451/31672726-984dcfa0-b35d-11e7-9e7d-d354b47e3694.png)
Cannot read property 'string' of undefined · Issue #2517 · aksonov/react-native-router-flux · GitHub
![javascript - undefined is not an object (evaluating 'Component.propTypes') - React Native 0.61.5 - Stack Overflow javascript - undefined is not an object (evaluating 'Component.propTypes') - React Native 0.61.5 - Stack Overflow](https://i.stack.imgur.com/PCI5h.png)