react prop-types: custom validators not firing

Question

In the official React documentation, it is stated that one can specify a custom validator for type checking.

---

My custom implementation of a validator below does however never execute and I cannot figure out why that is.

In the following example, funcWithArgs should be used to validate a function based on the # of its arguments, as for instance an "onClick" function here takes 1 single arg. However, funcWithArgs never executes.

const funcWithArgs = argCount => (props, propName, componentName) => {
  var func = props[propName];
  if (typeof func !== 'function' || func.length !== argCount) {
    return new Error(
      `${propName} must be a function with ${argCount} number arguments`,
    );
  }
};


Component.propTypes = {
  onClick: funcWithArgs(1)
}

What am I missing?

Answer 1

funcWithArgs is executing. It's returning an error, which isn't being handled. Replacing return new Error with console.log prints the propName message in a browser console, demonstrating that the function is being called.

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