fluent-transpiler/cli.js

Transpile Fluent (ftl) files into optimized, tree-shakable, JavaScript EcmaScript Modules (esm).

#!/usr/bin/env node
// Copyright 2026 will Farrell, and fluent-transpiler contributors.
// SPDX-License-Identifier: MIT

import { stat, writeFile } from "node:fs/promises";
import { Command, Option } from "commander";
import { compileFiles } from "./index.js";

const fileExists = async (filepath) => {
	const stats = await stat(filepath);
	if (!stats.isFile()) {
		throw new Error(`${filepath} is not a file`);
	}
};

new Command()
	.name("ftl")
	.description("Compile Fluent (.ftl) files to JavaScript (.js or .mjs)")
	.argument(
		"<inputs...>",
		"Paths to the Fluent file(s) to compile. Multiple files are joined in order; ids must be unique across the set.",
	)
	.requiredOption(
		"--locale <locale...>",
		"What locale(s) to be used. Multiple can be set to allow for fallback. i.e. en-CA",
	)
	.addOption(
		new Option("--comments", "Include comments in output file.").preset(true),
	)
	.addOption(
		new Option(
			"--include-key <includeMessageKey...>",
			"Allowed messages to be included. Default to include all.",
		),
	)
	.addOption(
		new Option(
			"--exclude-key <excludeMessageKey...>",
			"Ignored messages to be excluded. Default to exclude none.",
		),
	)
	.addOption(
		new Option(
			"--exclude-value <excludeMessageValue>",
			"Set message to an empty string when it contains this value. Default to not allowing empty strings.",
		),
	)
	.addOption(
		new Option(
			"--variable-notation <variableNotation>",
			"What variable notation to use with exports",
		)
			.choices(["camelCase", "pascalCase", "constantCase", "snakeCase"])
			.default("camelCase"),
	)
	.addOption(
		new Option(
			"--disable-minify",
			"If disabled, all exported messages will have the same interface `(params) => ({value, attributes})`.",
		).preset(true),
	)
	.addOption(
		new Option(
			"--use-isolating",
			"Wrap placeable with \\u2068 and \\u2069.",
		).preset(true),
	)
	.addOption(
		new Option(
			"-o, --output <output>",
			"Path to store the resulting JavaScript file. Will be in ESM.",
		),
	)
	.action(async (inputs, options) => {
		options.comments = options.comments ?? false;
		try {
			for (const input of inputs) {
				await fileExists(input);
			}

			const js = await compileFiles(inputs, options);
			if (options.output) {
				await writeFile(options.output, js, "utf8");
			} else {
				console.log(js);
			}
		} catch (e) {
			console.error(`Error: ${e.message}`);
			process.exit(1);
		}
	})
	.parse();