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Reatom

Debugging

For debugging, we recommend using the @reatom/logger package, which is included in the @reatom/framework. It logs all you actions and atoms changes in the console if you named it properly.

Installation

#
Terminal window
npm i @reatom/logger

After the installation is finished, you need to connect the logger to the reatom context.

import { createCtx } from '@reatom/core'
import { connectLogger } from '@reatom/logger'


const ctx = createCtx()


if (import.meta.env.DEV) {
  connectLogger(ctx)
}

Usage

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The immutable nature of reatom gives us incredible possibilities for debugging any data flow, whether synchronous or asynchronous. Let’s start with a simple example.

import { createCtx, atom, action } from '@reatom/core'
import { connectLogger } from '@reatom/logger'


const ctx = createCtx()


if (import.meta.env.DEV) {
  connectLogger(ctx)
}


const counterAtom = atom(0, 'counterAtom')
const doubledAtom = atom((ctx) => counterAtom * 2, 'doubledAtom')
const increment = action((ctx) => counterAtom(ctx, (state) => state + 1), 'increment')


ctx.subscribe(doubledAtom, () => {})


increment(ctx, 24)

Here is what we see in logs:

Reatom 1 transaction
├─ 3:37:34 PM 477ms
├─ increment
│  └─ 1
├─ counterAtom
│  ├─ cause: "<-- increment"
│  ├─ history: [...]
│  ├─ newState: 1
│  ├─ oldState: 0
│  └─ patch: {...}
├─ doubledAtom
│  ├─ cause: "<-- counterAtom <-- increment"
│  ├─ history: [...]
│  ├─ newState: 2
│  ├─ oldState: 0
│  └─ patch: {...}

Records come in pairs: the atom and its new state value. Under the atom name record, you can find a few properties:

  • cause: Describes why this update happened and what triggered it.
  • history: Shows the atom values before the update.

Check out the @reatom/logger package documentation for available options.

Try to use @reatom/eslint-plugin to automate the names indication.