Middleware Adaptation with Type Guards

Demonstrate how to implement a type guard in middleware to ensure incoming actions are string-typed as per Redux v5.0.0 requirements.

function isStringTypedAction(action) {
  // User-defined type guard that checks whether action.type is a string
  return typeof action.type === 'string';
}

Defines a user-defined type guard to verify if the 'type' property of the incoming action is a string, adhering to the new Redux v5.0.0 string-typed action requirement.

import { Middleware } from 'redux';

// Typed Middleware using the type guard
const stringTypedActionMiddleware = store => next => action => {
  if (isStringTypedAction(action)) {
    // Proceed with the action that is verified to be string-typed
    next(action);
  } else {
    // Handle or log actions that do not satisfy the type guard
    console.error('Invalid action type:', action);
  }
};

Implements the middleware with the defined type guard. This middleware first checks incoming actions with the isStringTypedAction guard and passes through only those with string-typed 'type' properties, logging an error for invalid actions.