Can I use both ES6 and ES5 in the same React codebase?
<p>I have the following gulpfile.js:</p>

<pre><code>var gulp = require('gulp');
var browserify = require('gulp-browserify');
var concat = require('gulp-concat');

gulp.task('browserify', function() {
    gulp.src('js/ScheduleMain.js')
      .pipe(browserify({transform:'reactify'}))
      .pipe(concat('ScheduleMain.js'))
      .pipe(gulp.dest('static/dist/js'));
    gulp.src('js/ConfidenceMain.js')
      .pipe(browserify({transform:'reactify'}))
      .pipe(concat('ConfidenceMain.js'))
      .pipe(gulp.dest('static/dist/js'));
});

gulp.task('default',['browserify']);

gulp.task('watch', function() {
    gulp.watch('src/**/*.*', ['default']);
});
</code></pre>

<p>As you can see I have two source files that need transforming. ScheduleMain.js is written in es5 and builds fine. I want to write my new application (ConfidenceMain.js) in es6 and possible transform it to es5 for build. I am a bit confused on how to do this (or rather if it is at all recommended).</p>

<p><strong>Bottom line:</strong> Can I move forward with new react projects written in es6 syntax despite having es5 code previously for other projects in the same code base?</p>