Difference between propType and PropType

Tell us what’s happening:
I was on following link and spend couple of hours trying to figure out why my name isn’t working until I had to get a hint, looks like it was camelCase and PasalCase e.g.
Camper.propTypes = { name: PropTypes.string.isRequired };
I am confused, the diff between propTypes and PropTypes
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Challenge: React - Review Using Props with Stateless Functional Components

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You might benefit from reviewing this challenge again.

PropTypes is library you import from the prop-types package to be able to define the propTypes property for a component.

By the way they are called you can pick some observations of their nature. For example PropTypes.string.isRequired. You can clearly see here PropTypes looks to be an object and it has the method/key name “string”. It serves as a dictionary of different “types” and their features. On the other hand, Camper.propTypes is defined on the Camper object and it stores some data related to that particular object. In the current case, we want to define what type of props Camper will contain.