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https://github.com/synacor/preact-i18n

Simple localization for Preact.
https://github.com/synacor/preact-i18n

Last synced: 3 months ago
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Simple localization for Preact.

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README

        

# preact-i18n 🌎 [![npm](https://img.shields.io/npm/v/preact-i18n.svg?style=flat)](https://npm.im/preact-i18n) [![travis](https://travis-ci.org/synacor/preact-i18n.svg?branch=master)](https://travis-ci.org/synacor/preact-i18n) [![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fsynacor%2Fpreact-i18n.svg?type=shield)](https://app.fossa.io/projects/git%2Bgithub.com%2Fsynacor%2Fpreact-i18n?ref=badge_shield)

Usage example

**Simple localization for Preact.**

- Tiny: about 1.3kb gzipped
- Supports dictionary and key scopes/namespaces while maintaining a global dictionary
- Supports nested dictionaries:
- Wrap your component in a default dictionary and scope key
- Wrap it again later on (in an app!) to override the defaults
- Supports pluralization of strings using nested objects.
- Supports template `{{fields}}` in definition values
- Has a companion [ESLint plugin](https://www.npmjs.com/package/eslint-plugin-preact-i18n) to help catch bugs early

* * *

- [Installation](#installation)
- [Getting Started](#getting-started)
- [Fallback Text](#fallback-text)
- [Pluralization and Templating](#pluralization-and-templating)
- [ESLint Plugin](#eslint-plugin)
- [API](#api)

## Preact Version Support

By default, the `master` branch of this repo supports preact 9 and below, and is published in normal patch/minor/major releases to the `latest` tag in npm. Support for preact X (versions 10+ of preact) is handled in the `preactX` branch and are always published to the `preactx` tag in npm. When preact X obtains widespread adoption, the `master` branch of this project will support preact X and a new major version under `latest` tag will be published to in npm.

## Installation

```sh
npm install --save preact-i18n

# For TypeScript Definitions
npm install --save-dev @types/preact-i18n
```

## Getting Started

1. Create a definition. Typically JSON files, we'll call ours `fr.json`:

```json
{
"news": {
"title": "Nouvelles du Monde",
"totalStories": {
"none": "Aucun article",
"one": "Un article",
"many": "{{count}} articles"
}
}
}
```

2. Expose the definition to your whole app via ``:

```js
import { IntlProvider } from 'preact-i18n';
import definition from './fr.json';

render(



);
```

3. Use `` to translate string literals:

```js
import { Text } from 'preact-i18n';

// Assume the "stories" prop is a list of news stories.
const App = ({ stories=[] }) => (



{/* Default fallback text example: */}
World News



{/* Pluralization example: */}



);
```

That's it!

### Fallback Text

Rendering our example app with an empty definition _(or without the Provider)_ will attempt to use any text contained within `..` as fallback text.

In our example, this would mean rendering without a definition for `news.title` would produce `

World News

`.

If we provide a definition that has a `title` key inside a `news` object, that value will be rendered instead.

### Pluralization and Templating

In our example, `` is using `` as a convenient way to do pluralization and templating. In our definition, `news.totalStories` is an Object with pluralization keys. The values in that object will be selected based on an integer `plural` prop passed to ``.

Any definition value _(including pluralization values)_ can contain `{{field}}` placeholders. These placeholders get replaced with matched keys in an object passed as the `fields` prop. In our example, the "many" plural form is such a template - it will render `"5 articles"` when `fields={{ count: 5 }}`.

The available forms for specifying pluralization values are as follows:

- `"key": { "singular":"apple", "plural":"apples" }`
- `"key": { "none":"no apples", "one":"apple", "many":"apples" }`
- `"key": { "zero":"no apples", "one":"apple", "other":"apples" }`
- `"key": ["apples", "apple"]`

Taking `` from our example:

- `<.. plural={0}>` renders `Aucun article` _(no articles)_
- `<.. plural={1}>` renders `Un article` _(one article)_
- `<.. plural={2} fields={{ count: 2 }}>` renders `2 articles`
- `<.. plural={3} fields={{ count: 3 }}>` renders `3 articles`

In addition to [``](#Text), [`withText()`](#withText) and [``](#Localizer) provide ways to translate more than just display text - HTML attributes, component props, arbitrary Strings, etc.

## ESLint Plugin

A companion ESLint plugin exists, [eslint-plugin-preact-i18n](https://www.npmjs.com/package/eslint-plugin-preact-i18n), which has several rules that help spot common issues like un-i18n'd text, misconfigured tags, and missing keys, that are beneficial in spotting defects early and ensuring that your application is properly i18n'd.

* * *

## API

#### Table of Contents

- [IntlProvider](#intlprovider)
- [Parameters](#parameters)
- [Examples](#examples)
- [Localizer](#localizer)
- [Parameters](#parameters-1)
- [Examples](#examples-1)
- [MarkupText](#markuptext)
- [Parameters](#parameters-2)
- [Examples](#examples-2)
- [Text](#text)
- [Parameters](#parameters-3)
- [Examples](#examples-3)
- [withText](#withtext)
- [Parameters](#parameters-4)
- [Examples](#examples-4)
- [intl](#intl)
- [Parameters](#parameters-5)

### IntlProvider

`` is a nestable internationalization definition provider.
It exposes an Intl scope & definition into the tree,
making them available to descendant components.

> **Note:** When nested, gives precedence to keys higher up the tree!
> This means lower-level components can set their defaults by wrapping themselves
> in an ``, but still remain localizable by their parent components.

#### Parameters

- `props`
- `props.scope` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)?** Nest `definition` under a root key, and set the active scope for the tree (essentially prefixing all `` keys).
- `props.mark` **[Boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** If `true`, all `` elements will be shown with a red/green background indicating whether they have valid Intl keys. (optional, default `false`)
- `props.definition` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** Merge the given definition into the current intl definition, giving the _current_ definition precedence (i.e., only adding keys, acting as defaults) (optional, default `{}`)

#### Examples

```javascript
// generally imported from a JSON file:
let definition = {
foo: 'Le Feux'
};

The Foo

// This will render the text:
"Le Feux"
```

### Localizer

`` is a Compositional Component.
It "renders" out any `` values in its child's props.

#### Parameters

- `props` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)**
- `props.children` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** Child components with props to localize.
- `context` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)**
- `context.intl` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** [internal] dictionary and scope info

#### Examples

```javascript

} />

// produces:

```

```javascript

Open Source Software}>
OSS

// produces:
OSS
```

### MarkupText

`` is just like [Text](#text) but it can also contain html markup in rendered strings. It wraps its contents in a `` tag.

#### Parameters

- `props` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** props
- `props.id` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** Key to look up in intl dictionary, within any parent scopes (`$scope1.$scope2.$id`)
- `props.fields` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** Values to inject into template `{{fields}}`. Values in the `fields` object will be coerced to strings, with the exception of `` nodes which will be resolved to their translated value (optional, default `{}`)
- `props.plural` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** Integer "count", used to select plural forms
- `context` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)**
- `context.intl` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** [internal] dictionary and scope info

#### Examples

```javascript
// If there is no dictionary in context..
The Foo
// ..produces the vnode:
The Foo
```

```javascript
// Given a dictionary and some fields..
{{bar}}' }}>
The Foo

// ..produces the vnode:
Le Feux BEAR
```

```javascript
// Within a scope, both `id` and the definition are namespaced..
Feux' }}>
The Foo

// ..produces the vnode:
Le Feux
```

```javascript
// renders nothing if there is no key match and no fallback


// ..produces the vnode:

```

### Text

`` renders internationalized text.
It attempts to look up translated values from a dictionary in context.

Template strings can contain `{{field}}` placeholders,
which injects values from the `fields` prop.

When string lookup fails, renders its children as fallback text.

#### Parameters

- `props` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** props
- `props.id` **[String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** Key to look up in intl dictionary, within any parent scopes (`$scope1.$scope2.$id`)
- `props.plural` **[Number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** Integer "count", used to select plural forms
- `props.fields` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** Values to inject into template `{{fields}}`. Values in the `fields` object will be coerced to strings, with the exception of `` nodes which will be resolved to their translated value (optional, default `{}`)
- `props.children`
- `context` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)**
- `context.intl` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** [internal] dictionary and scope info

#### Examples

```javascript
// If there is no dictionary in context..
The Foo
// ..produces the text:
"The Foo"
```

```javascript
// Given a dictionary and some fields..

The Foo

// ..produces the text:
"Le Feux BEAR"
```

```javascript
// Within a scope, both `id` and the definition are namespaced..

The Foo

// ..produces the text:
"Le Feux"
```

### withText

`@withText()` is a Higher Order Component, often used as a decorator.

It wraps a child component and passes it translations
based on a mapping to the dictionary & scope in context.

#### Parameters

- `mapping` **([Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object) \| [Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function) \| [String](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String))** Maps prop names to intl keys (or `` nodes).

#### Examples

```javascript
@withText({
placeholder: 'user.placeholder'
})
class Foo {
// now the `placeholder` prop is our localized String:
render({ placeholder }) {
return
}
}
```

```javascript
@withText({
placeholder: fallback text
})
class Foo {
render({ placeholder }) {
return
}
}
```

```javascript
@withText('user.placeholder')
class Foo {
// for Strings/Arrays, the last path segment becomes the prop name:
render({ placeholder }) {
return
}
}
```

Works with functional components, too

```javascript
const Foo = withText('user.placeholder')( props =>

)
```

getWrappedComponent() returns wrapped child Component

```javascript
const Foo = () =>

;
const WrappedFoo = withText('user.placeholer')(Foo);
WrappedFoo.getWrappedComponent() === Foo; // true
```

### intl

Higher-order function that creates an `` wrapper component for the given component. It
takes two forms depending on how many arguments it's given:
It can take a functional form like:
intl(ComponentToWrap, options)

or it can take an annotation form like:

#### Parameters

- `Child`
- `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** If there are two arguments, the second argument is Passed as `props` to ``
- `options.scope` Nest `definition` under a root key, and set the active scope for the tree (essentially prefixing all `` keys).
- `options.definition` Merge the given definition into the current intl definition, giving the _current_ definition precedence (i.e., only adding keys, acting as defaults) (optional, default `{}`)

## License

[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fsynacor%2Fpreact-i18n.svg?type=large)](https://app.fossa.io/projects/git%2Bgithub.com%2Fsynacor%2Fpreact-i18n?ref=badge_large)