At least one required prop in React

PropTypes actually can take a custom function as an argument so you could do something like this:

MyComponent.propTypes = {  data: (props, propName, componentName) => {    if (!props.data && !props.url) {      return new Error(`One of props 'data' or 'url' was not specified in '${componentName}'.`);    }  },  url: (props, propName, componentName) => {    if (!props.data && !props.url) {      return new Error(`One of props 'url' or 'data' was not specified in '${componentName}'.`);    }  }}

which allows for customer Error messaging. You can only return null or an Error when using this method

You can find more info on that here

https://facebook.github.io/react/docs/typechecking-with-proptypes.html#react.proptypes

from the react docs:

// 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(        'Invalid prop `' + propName + '` supplied to' +        ' `' + componentName + '`. Validation failed.'      );    }  },

A more concise version of @finalfreq's solution:

const requiredPropsCheck = (props, propName, componentName) => {  if (!props.data && !props.url) {    return new Error(`One of 'data' or 'url' is required by '${componentName}' component.`)  }}Markdown.propTypes = {  data: requiredPropsCheck,  url: requiredPropsCheck,}

Adding on top of finalfreq answer and relating to kousha comment to it.

I had a button component that required either icon or title. Make sure at least one of the is there like in the above answer, after that check its type can be validated like so:

Button.propTypes = {  icon: (props, propName, componentName) => {    if (!props.icon && !props.title) {      return new Error(`One of props 'icon' or 'title' was not specified in '${componentName}'.`)    }    if (props.icon) {      PropTypes.checkPropTypes({        icon: PropTypes.string, // or any other PropTypes you want      },      { icon: props.icon },      'prop',      'PrimaryButtonWithoutTheme')    }    return null  }  title: // same process}

For more info about PropTypes.checkPropTypes read here