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https://github.com/julienrf/play-jsmessages

Library to compute localized messages of your Play application on client side
https://github.com/julienrf/play-jsmessages

i18n javascript playframework

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Library to compute localized messages of your Play application on client side

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# Play JsMessages library



This library allows you to compute localized messages on client-side, in Play projects.



Basically, play-jsmessages takes the i18n messages of your Play application, sends them to the client-side as a JSON object and defines a JavaScript function returning a message value from a given language and the message key and arguments.



Take a look at the [Scala](/sample-scala) and [Java](/sample-java) samples to see it in action.



## Installation (using sbt)



Add a dependency on the following artifact:



```scala

libraryDependencies += "org.julienrf" %% "play-jsmessages" % "7.0.0"

```



The current 7.0.0 version is compatible with Play 3.0 and Scala 2.13 and 3.3.



Previous versions are available here:

 * [`6.0.0`](https://github.com/julienrf/play-jsmessages/tree/v6.0.0) for play-2.9 ;

 * [`5.0.0`](https://github.com/julienrf/play-jsmessages/tree/v5.0.0) for play-2.8 ;

 * [`4.0.0`](https://github.com/julienrf/play-jsmessages/tree/v4.0.0) for play-2.7 ;

 * [`3.0.0`](https://github.com/julienrf/play-jsmessages/tree/v3.0.0) for play-2.6 ;

 * [`2.1.0`](https://github.com/julienrf/play-jsmessages/tree/2.1.0) for play-2.5 ;

 * [`2.0.0`](https://github.com/julienrf/play-jsmessages/tree/2.0.0) for play-2.4 ;

 * [`1.6.2`](https://github.com/julienrf/play-jsmessages/tree/1.6.2) for play-2.3 ;

 * [`1.6.1`](https://github.com/julienrf/play-jsmessages/tree/1.6.1) for play-2.2 ;

 * [`1.5.2`](https://github.com/julienrf/play-jsmessages/tree/1.5.2) for play-2.2 ;

 * [`1.5.0`](https://github.com/julienrf/play-jsmessages/tree/1.5.0) for play-2.1 ;

 * [`1.3`](https://github.com/julienrf/play-jsmessages/tree/403dc8d7248c965c827b70edeff55016ae274bef) for play-2.0 ;

 * [`1.2.1`](https://github.com/julienrf/play-jsmessages/tree/cc52b23dae9997b77da3cbccf6d22b60a557c2ee) for play-2.0.



## API Documentation



You can browse the online [scaladoc](https://www.javadoc.io/doc/org.julienrf/play-jsmessages_2.12).



## Quick start



### Select which messages you want to support on client-side



#### Get a `JsMessagesFactory`



The `JsMessagesFactory` class is the starting point: it allows you to select which messages of your application

you want to support on client-side. You can use all the messages of the application or just a subset of them.



The simplest way to get a `JsMessagesFactory` is _via_ dependency injection:



```scala

import jsmessages.JsMessagesFactory

import javax.inject.Inject



class Application @Inject() (jsMessagesFactory: JsMessagesFactory) extends Controller {



}

```



The equivalent Java code is the following:



```java

import jsmessages.JsMessagesFactory;

import javax.inject.Inject;



public class Application extends Controller {



  @Inject

  public Application(JsMessagesFactory jsMessagesFactory) {



  }



}

```



The constructor of the `JsMessagesFactory` itself needs to be injected a `play.api.i18n.MessagesApi` parameter. By default,

Play defines a binding that uses a `play.api.i18n.DefaultMessagesApi`, but you can disable this binding if you want to use something else.



For more control, you can also manually instantiate your `JsMessagesFactory`:



```scala

val jsMessagesFactory = new JsMessagesFactory(someMessagesApi)

```



The equivalent Java code is the following:



```java

JsMessagesFactory jsMessagesFactory = new JsMessagesFactory(someMessagesApi);

```



Note that, in Scala, you may want to use the `JsMessagesFactoryComponents` trait that provides a `jsMessagesFactory: JsMessagesFactory`

member using an abstract `messagesApi: MessagesApi` member.



#### Select which messages to use



You can either use all your i18n messages:



```scala

val jsMessages = jsMessagesFactory.all

```



Or, just an extensive subset:



```scala

val jsMessages = jsMessagesFactory.subset("error.required", "error.number")

```



Or, finally, an intensive subset:



```scala

val jsMessages = jsMessagesFactory.filtering(_.startsWith("error."))

```



The equivalent Java code of the above expressions are the following:



```java

import jsmessages.JsMessages;

import play.libs.Scala;

JsMessages jsMessages = jsMessagesFactory.all();

JsMessages jsMessages = jsMessagesFactory.subset(Scala.varargs("error.required", "error.number"));

JsMessages jsMessages = jsMessagesFactory.filtering(new scala.runtime.AbstractFunction1() {

  @Override

  public Boolean apply(String key) {

    return key.startsWith("error.");

  }

});

```



### Generate a JavaScript asset …



#### … for the client’s preferred language



Then, you typically want to define an action returning a JavaScript resource containing all the machinery to compute

localized messages from client-side, using the client’s preferred lang:



```scala

val messages = Action { implicit request =>

  Ok(jsMessages(Some("window.Messages")))

}

```



Note that for this to work the `apply` method of `jsMessages` needs to have an implicit `play.api.i18n.Messages` value. You can

get one by mixing the `play.api.i18n.I18nSupport` trait in your controller.



Or in Java:



```java

@Inject

private MessagesApi messagesApi;



public Result messages(Http.Request request) {

    return ok(jsMessages.apply(Scala.Option("window.Messages"), this.messagesApi.preferred(request)));

}

```



The above code creates a Play action that returns a JavaScript program containing the localized messages of the

application for the client language and defining a global function `window.Messages`. This function returns a localized

message given its key and its arguments:



```javascript

console.log(Messages('greeting', 'Julien')); // will print e.g. "Hello, Julien!" or "Bonjour Julien!"

```



The JavaScript function can also be supplied alternative keys that will be used if the main key is not defined. Keys will be tried in order until a defined key is found:



```javascript

alert(Messages(['greeting', 'saluting'], 'Julien'));

```



The JavaScript function stores the messages map in a `messages` property that is publicly accessible so you can update the messages without reloading the page:



```javascript

// Update a single message

Messages.messages['greeting'] = 'Hi there {0}!';

// Update all messages

Messages.messages = {

  'greeting': 'Hello, {0}!'

}

```



#### … for all the languages



Alternatively, you can use the `all` method to generate a JavaScript program containing all the messages of the application

instead of just those of the client’s current language, making it possible to switch the language from client-side

without reloading the page:



```scala

val messages = Action {

  Ok(jsMessages.all(Some("window.Messages")))

}

```



The equivalent Java code is the following:



```java

public Result messages() {

    return ok(jsMessages.all(Scala.Option("window.Messages")));

}

```



In this case, the generated JavaScript function takes an additional parameter corresponding

to the language to use:



```javascript

console.log(Messages('en', 'greeting', 'Julien')); // "Hello, Julien!"

console.log(Messages('fr', 'greeting', 'Julien')); // "Bonjour Julien!"

```



Moreover, the `messages` property of the JavaScript function is a map of languages indexing maps of messages.



The JavaScript function can also be partially applied to fix its first parameter:



```javascript

val messagesFr = Messages('fr'); // Use only the 'fr' messages

console.log(messagesFr('greeting', 'Julien')); // "Bonjour Julien!"

```



Note: if you pass `undefined` as the language parameter, it will use the default messages.



## Changelog

* 7.0.0

  - Play 3.0.x compatibility.

 

* 6.0.0

  - Play 2.9.x compatibility.



* 5.0.0

  - Play 2.8.x compatibility.



* 4.0.0

  - Play 2.7.x compatibility, cross-compiled for Scala 2.13.



* 3.0.0

  - Play 2.6.x compatibility. All tests moved to scalatest+play and dependency injection.



* 2.0.0

  - Play 2.4.x compatibility.



* 1.6.2

  - Play 2.3.x compatibility.



* 1.6.1

  - Fix crash when `undefined` is passed as the language parameter (thanks to Paul Dijou).



* 1.6.0

  - Big changes in the API ;

  - Make it possible to return messages of all languages (thanks to Paul Dijou) ;

  - Discard methods returning HTML, keep just JavaScript.



* 1.5.2

  - Export the `messages` property on client-side (thanks to Paul Dijou).



* 1.5.1

  - Play 2.2.x compatibility.



* 1.5.0

  - Fix the `subset` method of the Java API (thanks to Seppel Hardt) ;

  - Refactor the whole API in order to make it more extensible (thanks to Jacques Bachellerie).



## License



This content is released under the [MIT License](http://opensource.org/licenses/mit-license.php).