logger

logger adds console groups around state updates. It is useful while shaping a store or debugging reducer actions.

Signature

logger<T>(initialState: T | Store<T>, options?: LoggerOptions): Store<T>
logger(options?: LoggerOptions): <T>(initialState: T | Store<T>) => Store<T>

type LoggerOptions = {
  collapsed?: boolean;
  diff?: boolean;
  timestamp?: boolean;
};

Example

import { logger } from '@ilokesto/state/middleware';

const store = logger({ count: 0 }, { collapsed: true, diff: true, timestamp: true });

store.setState((state) => ({ count: state.count + 1 }));

What gets logged

• update title with the action name when reducer middleware supplied one,
• previous state,
• next state,
• optional timestamp,
• optional shallow-ish JSON diff for object keys.

Practical notes

logger is skipped when process.env.NODE_ENV === "production". The diff output is best-effort debugging information based on JSON serialization, not a formal patch. Use it to inspect flow, not to drive application logic.