generator-ramp-webextension-kickstart/app/templates/tasks/locales.js

Yeoman generator

import gulp from 'gulp'
import gulpif from 'gulp-if'
import livereload from 'gulp-livereload'
import args from './lib/args'

gulp.task('locales', () => {
  return gulp.src('app/_locales/**/*.json')
    .pipe(gulp.dest(`dist/${args.vendor}/_locales`))
    .pipe(gulpif(args.watch, livereload()))
})