i18next-http-backend
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i18next-http-backend is a backend layer for i18next using in Node.js, in the browser and for Deno.
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# Introduction
[](https://github.com/i18next/i18next-http-backend/actions?query=workflow%3Anode)
[](https://github.com/i18next/i18next-http-backend/actions?query=workflow%3Adeno)
[](https://www.npmjs.com/package/i18next-http-backend)
This is a simple i18next backend to be used in Node.js, in the browser and for Deno. It will load resources from a backend server using the XMLHttpRequest or the fetch API.
Get a first idea on how it is used in [this i18next crash course video](https://youtu.be/SA_9i4TtxLQ?t=953).
It's based on the deprecated [i18next-xhr-backend](https://github.com/i18next/i18next-xhr-backend) and can mostly be used as a drop-in replacement.
*[Why i18next-xhr-backend was deprecated?](https://github.com/i18next/i18next-xhr-backend/issues/348#issuecomment-663060275)*
## Advice:
If you don't like to manage your translation files manually or are simply looking for a [better management solution](https://locize.com), take a look at [i18next-locize-backend](https://github.com/locize/i18next-locize-backend). The i18next [backed plugin](https://www.i18next.com/overview/plugins-and-utils#backends) for 🌐 [locize](https://locize.com) ☁️.
*To see [i18next-locize-backend](https://github.com/locize/i18next-locize-backend) in a working app example, check out:*
- *[this react-tutorial](https://github.com/locize/react-tutorial) starting from [Step 2](https://github.com/locize/react-tutorial#step-2---use-the-locize-cdn)*
- *[this guide](https://locize.com/blog/react-i18next/) starting from the step of [replacing i18next-http-backend with i18next-locize-backend](https://locize.com/blog/react-i18next/#how-look)*
- *[this Angular blog post](https://locize.com/blog/angular-i18next/) [introducing i18next-locize-backend](https://locize.com/blog/angular-i18next/#how-look)*
- *[the code integration part](https://www.youtube.com/watch?v=TFV_vhJs5DY&t=294s) in this [YouTube video](https://www.youtube.com/watch?v=TFV_vhJs5DY)*
## Troubleshooting
Make sure you set the `debug` option of i18next to `true`. This will maybe log more information in the developer console.
**Seeing failed http requests, like 404?**
Are you using a [language detector](https://github.com/i18next/i18next-browser-languageDetector) plugin that detects region specific languages you are not providing? i.e. you provide `'en'` translations but you see a `'en-US'` request first?
This is because of the default `load` [option](https://www.i18next.com/overview/configuration-options) set to `'all'`.
Try to set the `load` [option](https://www.i18next.com/overview/configuration-options) to `'languageOnly'`
```javascript
i18next.init({
load: 'languageOnly',
// other options
})
```
# Getting started
Source can be loaded via [npm](https://www.npmjs.com/package/i18next-http-backend) or [downloaded](https://github.com/i18next/i18next-http-backend/blob/master/i18nextHttpBackend.min.js) from this repo.
There's also the possibility to directly import it via a CDN like [jsdelivr](https://cdn.jsdelivr.net/npm/i18next-http-backend@1.3.1/i18nextHttpBackend.min.js) or [unpkg](https://unpkg.com/i18next-http-backend@1.3.1/i18nextHttpBackend.min.js) or similar.
```bash
# npm package
$ npm install i18next-http-backend
```
Wiring up:
```js
import i18next from 'i18next';
import HttpApi from 'i18next-http-backend';
i18next.use(HttpApi).init(i18nextOptions);
```
for Deno:
```js
import i18next from 'https://deno.land/x/i18next/index.js'
import Backend from 'https://deno.land/x/i18next_http_backend/index.js'
i18next.use(Backend).init(i18nextOptions);
```
for plain browser:
```html
<script src="https://cdn.jsdelivr.net/npm/i18next-http-backend@1.3.1/i18nextHttpBackend.min.js"></script>
<!-- an example can be found in example/jquery/index.html -->
```
```js
i18next.use(i18nextHttpBackend).init(i18nextOptions);
```
- As with all modules you can either pass the constructor function (class) to the i18next.use or a concrete instance.
- If you don't use a module loader it will be added to `window.i18nextHttpBackend`
## Backend Options
```js
{
// path where resources get loaded from, or a function
// returning a path:
// function(lngs, namespaces) { return customPath; }
// the returned path will interpolate lng, ns if provided like giving a static path
// the function might return a promise
// returning falsy will abort the download
//
// If not used with i18next-multiload-backend-adapter, lngs and namespaces will have only one element each,
// If used with i18next-multiload-backend-adapter, lngs and namespaces can have multiple elements
// and also your server needs to support multiloading
// /locales/resources.json?lng=de+en&ns=ns1+ns2
// Adapter is needed to enable MultiLoading https://github.com/i18next/i18next-multiload-backend-adapter
// Returned JSON structure in this case is
// {
// lang : {
// namespaceA: {},
// namespaceB: {},
// ...etc
// }
// }
loadPath: '/locales/{{lng}}/{{ns}}.json',
// path to post missing resources, or a function
// function(lng, namespace) { return customPath; }
// the returned path will interpolate lng, ns if provided like giving a static path
//
// note that this only works when initialized with { saveMissing: true }
// (see https://www.i18next.com/overview/configuration-options)
addPath: '/locales/add/{{lng}}/{{ns}}',
// parse data after it has been fetched
// in example use https://www.npmjs.com/package/json5 or https://www.npmjs.com/package/jsonc-parser
// here it removes the letter a from the json (bad idea)
parse: function(data) { return data.replace(/a/g, ''); },
// parse data before it has been sent by addPath
parsePayload: function(namespace, key, fallbackValue) { return { key: fallbackValue || "" } },
// parse data before it has been sent by loadPath
// if value returned it will send a POST request
parseLoadPayload: function(languages, namespaces) { return undefined },
// allow cross domain requests
crossDomain: false,
// allow credentials on cross domain requests
withCredentials: false,
// overrideMimeType sets request.overrideMimeType("application/json")
overrideMimeType: false,
// custom request headers sets request.setRequestHeader(key, value)
customHeaders: {
authorization: 'foo',
// ...
},
// can also be a function, that returns the headers
customHeaders: () => ({
authorization: 'foo',
// ...
}),
requestOptions: { // used for fetch, can also be a function (payload) => ({ method: 'GET' })
mode: 'cors',
credentials: 'same-origin',
cache: 'default'
},
// define a custom request function
// can be used to support XDomainRequest in IE 8 and 9
//
// 'options' will be this entire options object
// 'url' will be passed the value of 'loadPath'
// 'payload' will be a key:value object used when saving missing translations
// 'callback' is a function that takes two parameters, 'err' and 'res'.
// 'err' should be an error
// 'res' should be an object with a 'status' property and a 'data' property containing a stringified object instance beeing the key:value translation pairs for the
// requested language and namespace, or null in case of an error.
request: function (options, url, payload, callback) {},
// adds parameters to resource URL. 'example.com' -> 'example.com?v=1.3.5'
queryStringParams: { v: '1.3.5' },
reloadInterval: false // can be used to reload resources in a specific interval (milliseconds) (useful in server environments)
}
```
Options can be passed in:
**preferred** - by setting options.backend in i18next.init:
```js
import i18next from 'i18next';
import HttpApi from 'i18next-http-backend';
i18next.use(HttpApi).init({
backend: options,
});
```
on construction:
```js
import HttpApi from 'i18next-http-backend';
const HttpApi = new HttpApi(null, options);
```
via calling init:
```js
import HttpApi from 'i18next-http-backend';
const HttpApi = new HttpApi();
HttpApi.init(null, options);
```
## TypeScript
To properly type the backend options, you can import the `HttpBackendOptions` interface and use it as a generic type parameter to the i18next's `init` method, e.g.:
```ts
import i18n from 'i18next'
import HttpBackend, { HttpBackendOptions } from 'i18next-http-backend'
i18n
.use(HttpBackend)
.init<HttpBackendOptions>({
backend: {
// http backend options
},
// other i18next options
})
```
---
<h3 align="center">Gold Sponsors</h3>
<p align="center">
<a href="https://locize.com/" target="_blank">
<img src="https://raw.githubusercontent.com/i18next/i18next/master/assets/locize_sponsor_240.gif" width="240px">
</a>
</p>
---
**From the creators of i18next: localization as a service - locize.com**
A translation management system built around the i18next ecosystem - [locize.com](https://locize.com).
With using [locize](http://locize.com/?utm_source=react_i18next_readme&utm_medium=github) you directly support the future of i18next.
---