Webpack Loader for MessageFormat

A loader that parses input JSON, YAML and Java .properties files consisting of messages as objects of JavaScript message functions with a matching structure, all during the build of your application.

This package was previously named [messageformat-loader].

Installation

``
npm install --save-dev @messageformat/core @messageformat/loader
`

If you're intending to publish a library with external dependencies, you should also include the [runtime] as a dependency:

`
npm install @messageformat/runtime
`

Usage

After installation, you'll need to add the loader to your Webpack config.
Note the test value; you may want to customise the messages part to match whatever you're actually using, in particular if a generic match like /\.yaml$/ would overlap with another loader.

$3

`js
module.exports = {
module: {
rules: [
{
test: [/\bmessages\.(json|ya?ml)$/, /\.properties$/],
type: 'javascript/auto', // required by Webpack for JSON files
loader: '@messageformat/loader',
options: { locale: ['en'] }
}
]
}
};
`

With that in place, you'll be able to use your messages like this:

$3

`yaml
simple: 'A simple message.'
var: 'Message with {X}.'
plural: 'You have {N, plural, =0{no messages} one{1 message} other{# messages}}.'
select: '{GENDER, select, male{He has} female{She has} other{They have}} sent you a message.'
ordinal: 'The {N, selectordinal, one{1st} two{2nd} few{3rd} other{#th}} message.'
`

$3

`js
import messages from './messages.yaml';

messages.ordinal({ N: 1 });
// → 'The 1st message.'
`

Options

In addition to the [options accepted by @messageformat/core][options], the loader supports the following:

| Option | Type | Default | Description |
| ------------- | ----------------------------- | -------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| convert | boolean | false | Use [@messageformat/convert] to convert non-MessageFormat syntax and plural objects into MessageFormat. Use an object value to configure. |
| encoding | 'auto'/'utf8'/ 'latin1' | 'auto' | File encoding. With 'auto', attempts to detect 'utf8', falling back to 'latin1'. |
| locale | string[] | ['en'] | The [CLDR language codes] to pass to [MessageFormat][mf]. |
| propKeyPath | boolean | true | Parse dots . in .properties file keys as path separators, resulting in a multi-level message object. |

As MessageFormat is often used to provide multi-language support, it's important to include all of your supported locales in the options.locale value.
For example, using locale: ['en', 'fr'] would allow for imports from foo.en.properties and foo.fr.properties` to have their messages' locale set correctly, based on the file name.
Using a locale identifier as a key within the message file contents will also select that locale within it.

[messageformat-loader]: https://www.npmjs.com/package/messageformat-loader
[runtime]: https://messageformat.github.io/messageformat/api/runtime/
[options]: https://messageformat.github.io/messageformat/api/core.messageformatoptions/
[@messageformat/convert]: https://www.npmjs.com/package/@messageformat/convert
[cldr language codes]: http://www.unicode.org/cldr/charts/latest/supplemental/language_territory_information.html
[mf]: https://messageformat.github.io/messageformat/api/core.messageformat/

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Messageformat is an OpenJS Foundation project, and we follow its Code of Conduct.