# Redux DevTools Instrumentation

Redux enhancer used along with [Redux DevTools](https://github.com/reduxjs/redux-devtools) or [Remote Redux DevTools](https://github.com/zalmoxisus/remote-redux-devtools).

### Installation

```
yarn add @redux-devtools/instrument
```

### Usage

Add the store enhancer:

##### `store/configureStore.js`

```js
import { createStore, applyMiddleware, compose } from 'redux';
import thunk from 'redux-thunk';
import devTools from 'remote-redux-devtools';
import reducer from '../reducers';

// Usually you import the reducer from the monitor
// or apply with createDevTools as explained in Redux DevTools
const monitorReducer = (state = {}, action) => state;

export default function configureStore(initialState) {
  const enhancer = compose(
    applyMiddleware(...middlewares),
    // other enhancers and applyMiddleware should be added before the instrumentation
    instrument(monitorReducer, { maxAge: 50 }),
  );

  // Note: passing enhancer as last argument requires redux@>=3.1.0
  return createStore(reducer, initialState, enhancer);
}
```

### API

`instrument(monitorReducer, [options])`

- arguments
  - **monitorReducer** _function_ called whenever an action is dispatched ([see the example of a monitor reducer](https://github.com/reduxjs/redux-devtools/blob/master/packages/redux-devtools-log-monitor/src/reducers.ts#L34)).
  - **options** _object_
    - **maxAge** _number_ or _function_(currentLiftedAction, previousLiftedState) - maximum allowed actions to be stored on the history tree, the oldest actions are removed once `maxAge` is reached. Can be generated dynamically with a function getting current action as argument.
    - **shouldCatchErrors** _boolean_ - if specified as `true`, whenever there's an exception in reducers, the monitors will show the error message, and next actions will not be dispatched.
    - **shouldRecordChanges** _boolean_ - if specified as `false`, it will not record the changes till `pauseRecording(false)` is dispatched. Default is `true`.
    - **pauseActionType** _string_ - if specified, whenever `pauseRecording(false)` lifted action is dispatched and there are actions in the history log, will add this action type. If not specified, will commit when paused.
    - **shouldStartLocked** _boolean_ - if specified as `true`, it will not allow any non-monitor actions to be dispatched till `lockChanges(false)` is dispatched. Default is `false`.
    - **shouldHotReload** _boolean_ - if set to `false`, will not recompute the states on hot reloading (or on replacing the reducers). Default to `true`.
    - **trace** _boolean_ or _function_ - if set to `true`, will include stack trace for every dispatched action. You can use a function (with action object as argument) which should return `new Error().stack` string, getting the stack outside of reducers. Default to `false`.
    - **traceLimit** _number_ - maximum stack trace frames to be stored (in case `trace` option was provided as `true`). By default it's `10`. If `trace` option is a function, `traceLimit` will have no effect, that should be handled there like so: `trace: () => new Error().stack.split('\n').slice(0, limit+1).join('\n')` (`+1` is needed for Chrome where's an extra 1st frame for `Error\n`).

### License

MIT