API: addActionInterceptor

Register a global middleware function that intercepts chunk actions and async actions. Useful for validation, logging, or performance tracking.

function addActionInterceptor(
  interceptor: (
    ctx: ActionContext,
    next: () => any
  ) => any
): void

ActionContext Interface

interface ActionContext {
  /**
   * Name of the chunk (store) where the action is defined.
   */
  chunkName: string;

  /**
   * Name of the action or async action being executed.
   */
  actionName: string;

  /**
   * Arguments passed to the action.
   */
  args: any[];
}

Parameters

• interceptor: A function called before an action executes.

  • Receives a ctx object with chunkName, actionName, and args.
  • Must call next() to continue the chain and eventually run the action.
  • Can throw errors to halt execution or modify behavior.

Behavior

1. Registration: Call once at app startup. Interceptors apply globally in registration order.
2. Interception: For each action or async action invocation, all registered interceptors run sequentially.
3. Chaining: Each interceptor calls next() to pass control to the next interceptor or final action.
4. Error Handling: Throwing inside an interceptor stops further interceptors and prevents the action from running.

Note: Currently, interceptors apply to async actions. In the next release, support will expand to include separate interceptor types for sync actions, async actions, and general actions.

Example

import { addActionInterceptor } from "mobx-chunk";

// Validate that payload has an 'email' field when calling 'createUser'
addActionInterceptor((ctx, next) => {
  if (ctx.actionName === "createUser") {
    const [payload] = ctx.args;
    if (!payload || typeof payload.email !== "string") {
      throw new Error(
        `[ValidationError] ${ctx.chunkName}.${ctx.actionName} expects { email: string }`
      );
    }
  }
  // Continue to next interceptor or actual action
  return next();
});

Use addActionInterceptor to enforce data integrity, log user interactions, or measure performance across your mobx-chunk stores.