i18next

Description:

i18next

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.

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

Usage #
Simply declare the package in your pubspec.yaml
dependencies:
i18next: ^0.5.0
copied to clipboard
To use it with flutter's LocalizationsDelegate you first create I18NextLocalizationDelegate and register it in your WidgetsApp (MaterialApp or CupertinoApp).
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(...),
),
copied to clipboard
Then to access and use it, simply call
Widget build(BuildContext context) {
// It finds the i18next instance on the widgets tree via `Localizations.of`
I18Next.of(context).t(...);
...
}
copied to clipboard
But if you want to handle it yourself, then simply instantiate it:
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(...)
);
copied to clipboard
Syntax #
For the simple and straightforward usages:
{
"key": "Hello World!",
"nested": {
"key": "My nested key"
}
}
copied to clipboard
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'
copied to clipboard

Basic Interpolation:

{
"key": "Hello {{name}}!",
"grouped_key": "Hello {{grouped.name}}"
}
copied to clipboard
i18next.t('key', arguments: {'name': 'World'}); // 'Hello World!'
i18next.t('grouped_key', arguments: {'grouped': {'name': 'Grouped World'}}); // 'Hello Grouped World!'
copied to clipboard

Nesting:

{
"nesting1": "1 $t(nesting2)",
"nesting2": "2 $t(nesting3)",
"nesting3": "3"
}
copied to clipboard
i18next.t('nesting1'); // "1 2 3"
copied to clipboard

Plurals

{
"key": "item",
"key_plural": "items",
"keyWithCount": "{{count}} item",
"keyWithCount_plural": "{{count}} items"
}
copied to clipboard
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'
copied to clipboard
There are also ways of dealing with locales with multiple plural: zero, one, few, many, others (key identifier) (Unsupported)

Contexts like gender, are marked via underscores

{
"genderMessage": "They",
"genderMessage_male": "Him",
"genderMessage_female": "Her"
}
copied to clipboard
i18next.t('genderMessage'); // 'They'
i18next.t('genderMessage', context: 'male'); // 'Him'
i18next.t('genderMessage', context: 'female'); // 'Her'
copied to clipboard
And can be used with plurals
{
"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"
}
copied to clipboard
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'
copied to clipboard

Formatting

{
"key1": "{{text, uppercase}} just uppercased",
"key2": "The current date is {{now, datetime(format:dd/MM/yyyy)}}",
"key3": "Right now we are in {{now, datetime(format:MMM), uppercase}}."
}
copied to clipboard
i18next.t('key1', arguments: { 'text': 'my text' }); // 'MY TEXT just uppercased'
i18next.t('key2', arguments: { 'now': DateTime.now() }); // 'The current date is 21/01/2020'
i18next.t('key3', arguments: { 'now': DateTime.now() }); // 'Right now we are in JAN.'
copied to clipboard
There are other usages and possibilities as well, this is just an example of what is defined by this format.


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



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

// feature.json
{
"myKey": "This key is in my feature"
}
copied to clipboard
i18next.t('common:myKey'); // 'This key is in common'
i18next.t('feature:myKey'); // 'This key is in my feature'
copied to clipboard

Context/plural fallback mechanism:

{
"friend": "A friend",
"friend_female": "A girlfriend"
}
copied to clipboard
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'
copied to clipboard
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.