element-ui/build/bin/build-locale.js

var fs = require('fs');
var save = require('file-save');
var resolve = require('path').resolve;
var basename = require('path').basename;
var localePath = resolve(__dirname, '../../src/locale/lang');
var fileList = fs.readdirSync(localePath);

var transform = function(filename, name, cb) {
  require('babel-core').transformFile(resolve(localePath, filename), {
    plugins: [
      'add-module-exports',
      ['transform-es2015-modules-umd', {loose: true}]
    ],
    moduleId: name
  }, cb);
};

fileList.forEach(function(file) {
  var name = basename(file, '.js');

  transform(file, name, function(err, result) {
    if (err) {
      console.error(err);
    } else {
      var code = result.code;

      code = code
        .replace('define(\'', 'define(\'element/locale/')
        .replace('global.', 'global.ELEMENT.lang = global.ELEMENT.lang || {}; \n    global.ELEMENT.lang.');
      save(resolve(__dirname, '../../lib/umd/locale', file)).write(code);

      console.log(file);
    }
  });
});