> For the complete documentation index, see [llms.txt](https://devworkshops.gitbook.io/masteringvuejs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://devworkshops.gitbook.io/masteringvuejs/getting-started/lifecycles.md).

# Lifecycles

Vue.js has many lifecycle hooks that we can bind to and they are really useful when it comes to loading data dynamically or cleaning up variables when no longer needed. We're going to make a tiny change to our app which is not going to change behaviour but in the future will be used a lot.

Instead of populating the todos array in the data property, we going to do it in the created lifecycle hook. Update as **main.js** as displayed below:

{% code title="main.js" %}

```javascript
...
data: {
    todos: [],
...
},
created(){
    this.todos = [
        { id: 1, title: "Do this thing.", done: false, created: new Date(2019,1,1) },
        { id: 2, title: "Do another thing.", done: false, created: new Date(2019,3,1) },
        { id: 3, title: "Do many, many things!", done: false, created: new Date() },
        { id: 4, title: "This thing is done.", done: true, created: new Date() }
    ]
}
...
```

{% endcode %}

In a later module, we will update the created lifecycle hook to invoke an API and retrieve data from the server.

For more information about lifecycle hooks, you can check the [Vue.js documentation](https://vuejs.org/v2/guide/instance.html#Instance-Lifecycle-Hooks).


---

# 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://devworkshops.gitbook.io/masteringvuejs/getting-started/lifecycles.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.