build/lib/i18n.ts/processNlsFiles
export function processNlsFiles(opts: { fileHeader: string; languages: Language[] }): ThroughStream {
	return through(function (this: ThroughStream, file: File) {
		const fileName = path.basename(file.path);
		if (fileName === 'nls.metadata.json') {
			let json = null;
			if (file.isBuffer()) {
				json = JSON.parse((<Buffer>file.contents).toString('utf8'));
			} else {
				this.emit('error', `Failed to read component file: ${file.relative}`);
				return;
			}
			if (BundledFormat.is(json)) {
				processCoreBundleFormat(opts.fileHeader, opts.languages, json, this);
			}
		}
		this.queue(file);
	});
}