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https://github.com/nubank/i18next


https://github.com/nubank/i18next

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README

          

# i18next

![build](https://github.com/nubank/i18next/workflows/build/badge.svg) [![codecov](https://codecov.io/gh/nubank/i18next/branch/master/graph/badge.svg)](https://codecov.io/gh/nubank/i18next)

This is an adaptation of i18next standard for Dart with support for Flutter localization techniques. This package is still a work in progress.
Mind that this is still a pre-1.0.0 so breaking changes may occur frequently.

- [x] Support for variables
- [x] Support for namespaces
- [x] Support for context
- [x] Support for simple plural forms (one or plural)
- [x] Support for multiple plural forms (one, few, many, plural, ...)
- [x] Plural and context fallbacks
- [ ] Locale and namespace fallbacks
- [x] Get string or object tree
- [x] Support for nesting
- [ ] Sprintf support
- [x] Flutter's `LocalizationsDelegate` support
- [x] Asset bundle localizations data source (retrieves from `pubspec.yaml`). See the example for more details.
- [ ] Resource caching :wip:
- [ ] Retrieve resource files from server :wip:
- [ ] Custom post processing

## Usage

Simply declare the package in your `pubspec.yaml`

```yaml
dependencies:
i18next: ^0.0.1
```

To use it with flutter's `LocalizationsDelegate` you first create `I18NextLocalizationDelegate` and register it in your `WidgetsApp` (`MaterialApp` or `CupertinoApp`).

```dart
I18NextLocalizationDelegate(
locales: widget.locales,
// this data source is from where the delegate will retrieve the localizations from (namespaces Map)
dataSource: ...,
// optional extra options can be added here
options: I18NextOptions(...),
),
```

Then to access and use it, simply call

```dart
Widget build(BuildContext context) {
// It finds the i18next instance on the widgets tree via `Localizations.of`
I18Next.of(context).t(...);
...
}
```

But if you want to handle it yourself, then simply instantiate it:

```dart
I18Next(
locale,
// This store is from where i18next will attempt to retrieve the localizations from.
resourceStore: ...,
// Optional extra options can be added here
options: I18NextOptions(...)
);
```

## Syntax

For the simple and straightforward usages:

```json
{
"key": "Hello World!",
"nested": {
"key": "My nested key"
}
}
```

```dart
i18next.t('key'); // 'Hello World!'
i18next.t('nested.key'); // 'My nested key'

// unmapped keys usually return themselves (when graceful fallback fails)
i18next.t('unspecifiedKey'); // 'unspecifiedKey'
```

- Basic [Interpolation](https://www.i18next.com/translation-function/interpolation):

```json
{
"key": "Hello {{name}}!",
"grouped_key": "Hello {{grouped.name}}"
}
```

```dart
i18next.t('key', arguments: {'name': 'World'}); // 'Hello World!'
i18next.t('grouped_key', arguments: {'grouped': {'name': 'Grouped World'}}); // 'Hello Grouped World!'
```

- [Nesting](https://www.i18next.com/translation-function/nesting):

```json
{
"nesting1": "1 $t(nesting2)",
"nesting2": "2 $t(nesting3)",
"nesting3": "3"
}
```

```dart
i18next.t('nesting1'); // "1 2 3"
```

- [Plurals](https://www.i18next.com/translation-function/plurals)

```json
{
"key": "item",
"key_plural": "items",
"keyWithCount": "{{count}} item",
"keyWithCount_plural": "{{count}} items"
}
```

```dart
i18next.t('key', count: 0); // 'items'
i18next.t('key', count: 1); // 'item'
i18next.t('key', count: 5); // 'items'
i18next.t('keyWithCount', count: 0); // '0 items'
i18next.t('keyWithCount', count: 1); // '1 item'
i18next.t('keyWithCount', count: 5); // '5 items'
```

There are also ways of dealing with locales with multiple plural: `zero, one, few, many, others` ([key identifier](https://jsfiddle.net/sm9wgLze)) (**Unsupported**)

- Contexts like gender, are marked via underscores

```json
{
"genderMessage": "They",
"genderMessage_male": "Him",
"genderMessage_female": "Her"
}
```

```dart
i18next.t('genderMessage'); // 'They'
i18next.t('genderMessage', context: 'male'); // 'Him'
i18next.t('genderMessage', context: 'female'); // 'Her'
```

And can be used with plurals

```json
{
"friend": "A friend",
"friend_plural": "{{count}} friends",
"friend_male": "A boyfriend",
"friend_female": "A girlfriend",
"friend_male_plural": "{{count}} boyfriends",
"friend_female_plural": "{{count}} girlfriends"
}
```

```dart
i18next.t('friend'); // 'A friend'
i18next.t('friend', count: 1); // 'A friend'
i18next.t('friend', count: 100); // '100 friends'

i18next.t('friend', context: 'male', count: 1); // 'A boyfriend'
i18next.t('friend', context: 'female', count: 1); // 'A girlfriend'
i18next.t('friend', context: 'male', count: 100); // '100 boyfriends'
i18next.t('friend', context: 'female', count: 100); // '100 girlfriends'
```

- [Formatting](https://www.i18next.com/translation-function/formatting)

```json
{
"key1": "The current date is {{now, MM/DD/YYYY}}",
"key2": "{{text, uppercase}} just uppercased"
}
```

```dart
i18next.t('key1', arguments: { 'now': DateTime.now() }); // 'The current date is 01/01/2020'
i18next.t('key2', arguments: { 'text': 'my text' }); // 'MY TEXT just uppercased'
```

There are other usages and possibilities as well, this is just an example of what is defined by this format.

- [Namespaces](https://www.i18next.com/principles/namespaces): A namespace can be thought of as logical groupings of different sets of translations. In a given namespace you could have a set of languages, each with their own set of keys. They can also be understood as separate files.
For example:

- **common.json:** Things that are reused everywhere, eg. Button labels 'save', 'cancel'
- **validation.json:** All validation texts
- **glossary.json:** Words we want to be reused consistently inside texts

```json
// common.json
{
"myKey": "This key is in common"
}

// feature.json
{
"myKey": "This key is in my feature"
}
```

```dart
i18next.t('common:myKey'); // 'This key is in common'
i18next.t('feature:myKey'); // 'This key is in my feature'
```

- Context/plural fallback mechanism:

```json
{
"friend": "A friend",
"friend_female": "A girlfriend"
}
```

```dart
i18next.t('friend'); // 'A friend'

i18next.t('friend', count: 1); // 'A friend'
// It fallbacks to `friend` since `friend_plural` is not present
i18next.t('friend', count: 2); // 'A friend'

i18next.t('friend', context: 'female'); // 'A girlfriend'
// It fallbacks to `friend` since `friend_male` is not present
i18next.t('friend', context: 'male'); // 'A friend'
```

There is a way to also set the default namespace or a order of namespaces so a key knows where to start looking for the translation.