i18n.js

// app.translate('foo.bar') renders this.translations.foo.bar
// app.translate('foo.bar', 'baz') renders this.translations.foo.bar, replacing any ${} syntax with 'baz'
// app.translate('foo.bar', { hello: 'world' }) renders this.translations.foo.bar, replacing ${hello} with 'world'
translate (key, replace) {
	if (!this.translations) {
		return '';
	}

	let translation = this.translations;

	key = key.split('.');

	for (let k of key) {
		k = k.replace(/([a-z])([A-Z])/g, (match, before, after) => {
			return `${before}_${after.toLowerCase()}`
		}).toLowerCase();

		try {
			translation = translation[k];

			if (translation === undefined) {
				return '';
			}
		} catch (e) {
			return '';
		}
	}

	if (!!replace) {
		if (typeof replace === 'object') {
			for (let key in replace) {
				let value = replace[key];

				translation = translation.replace('${' + key + '}', value);
			}
		} else {
			translation = translation.replace(/\$\{[\w\d]+\}/gi, replace);
		}
	}

	return translation;
}

nice