@rr0/lang
v0.1.12
Published
Language and translation
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@rr0/lang
A typed, no-dependency language and translation lib.
- Support for standard template literals as placeholders in messages, with plural support.
- Translations implement interfaces, so:
- you cannot use a incorrect message, since the compiler allows only declared message keys.
- you cannot forget a translation, since all the compiler will enforce you to implement it.
Installation
Add @rr0/lang
as a dependency to your project:
npm install @rr0/lang --save
so that you can
import * from "@rr0/lang"
in your code.
Usage
- Create a common interface for your messages in every language. :
interface MyMessages extends KeyValue { hello: string; bye: string; }
}` - Create implementations of this interface with translations values:
class MyFrenchMessages implements MyMessages { hello = "Bonjour ${name}"; bye = "Au revoir"}
- Create a Translator with a given target language and grammar:
frTranslator = new Translator("fr", grammar_fr)
- Translate a message:
bonjour = frTranslator.translate(myFrMessages.hello, {name: "Jérôme"})
Plural support
You can use ${var:plural}
variant in a placeholder to force plural. The translator will then use the provided grammar
rules to render the message.
Translations
By default, messages and translators are separated, but you can use a Translation
, which is a Translator
that holds
its messages.
Example
Say we want to translate some message in two locales:
import {Translator, grammar_en, grammar_fr} from '@rr0/lang'
// #1
interface MyMessages extends KeyValue {
key1: string
}
// #2
class EnglishMessages implements MyMessages {
key1 = 'several ${param1:plural} and ${param2:plural} but one single ${param1} and ${param2}'
}
class FrenchMessages implements MyMessages {
key1 = 'plusieurs ${param1:plural} et ${param2:plural} mais un seul ${param1} et ${param2}'
}
// #3
const messages_en = new EnglishMessages()
const translator_en = new Translator('en', grammar_en)
const messages_fr = new FrenchMessages()
const translator_fr = new Translator('fr', grammar_fr)
// #4
const translated_en = translator_en.translate(messages_en.key1, {
param1: 'thing',
param2: 'party'
})
// translated_en = "several things and parties but one single thing and party"
const translated_fr = translator_fr.translate(messages_fr.key1, {
param1: 'cigare',
param2: 'cheval'
})
// translated_fr = "plusieurs cigares et chevaux mais un seul cigare et cheval"
A Translation
is a Translator
that holds its messages. For instance:
const messages = { dict: { key: 'value is ${param}' } }
const translation = new Translation('fr', grammar_fr, messages)
translation.add('newKey', 'new value is ${param}')
const translated = translation.translate(translation.messages.dict['newKey'], { param: 'paramValue' })
// translated = "new value is paramValue"