@fluent/syntax

What is @fluent/syntax?

@fluent/syntax is a JavaScript library for working with Fluent syntax, which is a localization system designed by Mozilla. It allows developers to parse, serialize, and manipulate Fluent translation files, making it easier to manage and work with localized content.

What are @fluent/syntax's main functionalities?

Parsing Fluent Syntax

This feature allows you to parse Fluent syntax strings into an abstract syntax tree (AST). The code sample demonstrates how to parse a simple Fluent message.

const { parse } = require('@fluent/syntax');
const source = `
hello = Hello, world!
`; 
const resource = parse(source);
console.log(resource);

Serializing Fluent Syntax

This feature allows you to serialize an AST back into Fluent syntax. The code sample demonstrates how to serialize a simple Fluent message.

const { serialize } = require('@fluent/syntax');
const resource = {
  type: 'Resource',
  body: [
    {
      type: 'Message',
      id: { type: 'Identifier', name: 'hello' },
      value: { type: 'Pattern', elements: [{ type: 'TextElement', value: 'Hello, world!' }] }
    }
  ]
};
const source = serialize(resource);
console.log(source);

Manipulating Fluent AST

This feature allows you to manipulate the AST of a Fluent message. The code sample demonstrates how to change the value of a message and serialize it back to Fluent syntax.

const { parse, serialize } = require('@fluent/syntax');
const source = `
hello = Hello, world!
`;
let resource = parse(source);
resource.body[0].value.elements[0].value = 'Hello, universe!';
const updatedSource = serialize(resource);
console.log(updatedSource);

Other packages similar to @fluent/syntax

messageformat

MessageFormat is a library for handling both pluralization and gender in messages. It is more focused on ICU MessageFormat syntax, which is different from Fluent syntax. While @fluent/syntax is designed for the Fluent localization system, messageformat is more general-purpose and can be used for various localization needs.

i18next

i18next is a widely-used internationalization framework for JavaScript. It provides a comprehensive solution for managing translations, including interpolation, pluralization, and context. Unlike @fluent/syntax, which is specific to Fluent syntax, i18next supports multiple formats and is highly extensible.

format-message

format-message is a library for formatting messages with ICU MessageFormat syntax. It provides similar functionality to @fluent/syntax but uses a different syntax standard. It is useful for applications that need to support complex message formatting and localization.

README

@fluent/syntax

@fluent/syntax is a tooling library for parsing, serializing, and working with the Fluent syntax. It's part of Project Fluent.

Installation

@fluent/syntax can be used both on the client-side and the server-side. You can install it from the npm registry or use it as a standalone script (as the FluentSyntax global).

npm install @fluent/syntax

How to use

import { parse, Resource } from "@fluent/syntax";

const res = parse(`
-brand-name = Foo 3000
welcome = Welcome, {$name}, to {-brand-name}!
`);

assert(res instanceof Resource);

The API reference is available at https://projectfluent.org/fluent.js/syntax.