checks provided files with and compares them to translation files to find missing translations
$ npm install --save-dev gulp-missing-translations
var gulp = require('gulp');
var missingTranslations = require('gulp-missing-translations');
gulp.task('translations', function() {
return gulp.src(['app/scripts/**/*.js', 'app/views/**/*.html'])
.pipe(missingTranslations({ translationsSrc: 'app/translations/*.json' }));
});