mirror of
https://github.com/nuxt/nuxt.git
synced 2024-11-24 14:45:15 +00:00
106 lines
4.2 KiB
Markdown
106 lines
4.2 KiB
Markdown
# Async data with Nuxt.js
|
|
|
|
## data (context)
|
|
|
|
> Nuxt.js *supercharges* the `data` method from vue.js to let you handle async operation before setting the component data.
|
|
|
|
`data` is called every time before loading the component (*only if attached to a route*). It can be called from the server-side or before navigating to the corresponding route.
|
|
|
|
The `data` method receives the context as the first argument, you can use it to fetch some data and return the component data. To make the data method asynchronous, Nuxt.js offers you 2 ways, choose the one you're the most familiar with:
|
|
|
|
1. returning a `Promise`, Nuxt.js will wait for the promise to be resolved before rendering the Component
|
|
2. Define a second argument which is a callback method to be called like this: `callback(err, data)`
|
|
|
|
Example with returning a `Promise`:
|
|
```js
|
|
export default {
|
|
data ({ params }) {
|
|
return axios.get(`https://my-api/posts/${params.id}`)
|
|
.then((res) => {
|
|
return { title: res.data.title }
|
|
})
|
|
}
|
|
}
|
|
```
|
|
|
|
Example with using the `callback` argument:
|
|
```js
|
|
export default {
|
|
data ({ params }, callback) {
|
|
axios.get(`https://my-api/posts/${params.id}`)
|
|
.then((res) => {
|
|
callback(null, { title: res.data.title })
|
|
})
|
|
}
|
|
}
|
|
```
|
|
|
|
And then, you can display the data inside your template:
|
|
|
|
```html
|
|
<template>
|
|
<h1>{{ title }}</h1>
|
|
</template>
|
|
```
|
|
|
|
## Context
|
|
|
|
List of all the available keys in `context`:
|
|
|
|
| Key | Type | Available | Description |
|
|
|-----|------|--------------|-------------|
|
|
| `isClient` | Boolean | Client & Server | Boolean to let you know if you're actually renderer from the client-side |
|
|
| `isServer` | Boolean | Client & Server | Boolean to let you know if you're actually renderer from the server-side |
|
|
| `isDev` | Boolean | Client & Server | Boolean to let you know if you're in dev mode, can be useful for caching some data in production |
|
|
| `route` | [vue-router route](https://router.vuejs.org/en/api/route-object.html) | Client & Server | `vue-router` route instance [see documentation](https://router.vuejs.org/en/api/route-object.html) |
|
|
| `store` | [vuex store](http://vuex.vuejs.org/en/api.html#vuexstore-instance-properties) | Client & Server | `Vuex.Store` instance. **Available only if `store: true` is set in `nuxt.config.js`** |
|
|
| `params` | Object | Client & Server | Alias of route.params |
|
|
| `query` | Object | Client & Server | Alias of route.query |
|
|
| `req` | [http.Request](https://nodejs.org/api/http.html#http_class_http_incomingmessage) | Server | Request from the node.js server. If nuxt is used as a middleware, the req object might be different depending of the framework you're using. |
|
|
| `res` | [http.Response](https://nodejs.org/api/http.html#http_class_http_serverresponse) | Server | Response from the node.js server. If nuxt is used as a middleware, the res object might be different depending of the framework you're using. |
|
|
| `redirect` | Function | Client & Server | Use this method to redirect the user to another route, the status code is used on the server-side, default to 302. `redirect([status,] path [, query])` |
|
|
| `error` | Function | Client & Server | Use this method to show the error page: `error(params)`. The `params` should have the fields `statusCode` and `message`. |
|
|
|
|
## Handling errors
|
|
|
|
Nuxt.js add the `error(params)` method in the `context`, you can call it to display the error page. `params.statusCode` will be also used to render the proper status code form the server-side.
|
|
|
|
Example with a `Promise`:
|
|
```js
|
|
export default {
|
|
data ({ params, error }) {
|
|
return axios.get(`https://my-api/posts/${params.id}`)
|
|
.then((res) => {
|
|
return { title: res.data.title }
|
|
})
|
|
.catch((e) => {
|
|
error({ statusCode: 404, message: 'Post not found' })
|
|
})
|
|
}
|
|
}
|
|
```
|
|
|
|
If you're using the `callback` argument, you can call it directly with the error, Nuxt.js will call the `error` method for you:
|
|
```js
|
|
export default {
|
|
data ({ params }, callback) {
|
|
axios.get(`https://my-api/posts/${params.id}`)
|
|
.then((res) => {
|
|
callback(null, { title: res.data.title })
|
|
})
|
|
.catch((e) => {
|
|
callback({ statusCode: 404, message: 'Post not found' })
|
|
})
|
|
}
|
|
}
|
|
```
|
|
|
|
## Demo
|
|
|
|
```bash
|
|
npm install
|
|
npm start
|
|
```
|
|
|
|
Go to [http://localhost:3000](http://localhost:3000) and navigate trough the app.
|