Custom Middlewares

A middleware is a function that wraps the store’s dispatch pipeline. The signature is the standard Redux-style triple-function:

import * as Core from '@golemui/core';

export const myMiddleware: Core.Middleware<Core.State, Core.Action> =
  (store) => (next) => (action) => {
    console.log('Before:', action.type, store.getState());
    const result = next(action);
    console.log('After:', store.getState());
    return result;
  };

Pass it through the middlewares prop of the form component (this stays as a separate prop, not inside formConfig).

Patterns

• Logging. Log every action and resulting state — useful during development.
• Persistence. Watch a subset of actions and persist the form state to localStorage.
• Schema validation. Validate every state mutation against a JSON Schema and reject invalid changes.
• Telemetry. Emit analytics events for specific user interactions.

See also

• Features / Middlewares — built-in middlewares and how to wire them.