> For the complete documentation index, see [llms.txt](https://guide-node-js.wishtack.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide-node-js.wishtack.io/node-js/error-management.md).

# Error Management

## Convention Node.js

Si le premier paramètre est non `null` alors une erreur s'est produite et les informations de l'erreur sont dans ce paramètre.

Si le premier paramètre est `null` alors il s'agit d'un succès.

```javascript
fs.readFile('wishtack.txt', function (error, data) {

    if (error !== null) {
        /* Something went wrong. */
        return;
    }

    /* Everything is just fine. */
    ...

});

```

Si l'erreur a une solution alternative *("retry" ou solution de backup)* alors gérez l'erreur immédiatement sinon il faut remonter l'erreur à l'utilisateur.

{% hint style="warning" %}
Aucune erreur ne doit être ignorée.
{% endhint %}

## Détection d'erreur avec l'objet `EventEmitter`

```javascript
const EventEmitter = require('events');

const emitter = new EventEmitter();

emitter.on('error', error => {
    /* Handle error case. */
});
```

{% hint style="danger" %}
Avec un `EventEmitter`, si l'erreur n'est pas capturée, une exception sera levée et interrompra le programme.
{% endhint %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://guide-node-js.wishtack.io/node-js/error-management.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.