<p dir="auto">Maybe it does not cover main idea of 6to5 compiler, but it will be great if we will have ability to specify for which environment we wrote our application.<br>
For example, I wrote some modern application of latest version of Firefox and Google Chrome, but according this table <a href="http://kangax.github.io/compat-table/es6/" rel="nofollow">http://kangax.github.io/compat-table/es6/</a>, we actually have native support for a lot of things from ES6 in these browsers.<br>
This means that it is not necessary to compile a lot of things into ES5.</p>
<p dir="auto">I like approach from <a href="https://github.com/postcss/autoprefixer#browsers">autoprefixer</a><br>
where we can configure our build like <code class="notranslate">last 2 versions</code> or <code class="notranslate">&gt; 5%.</code></p>
<p dir="auto">Possibly through a <code class="notranslate">blacklistUserAgent</code> option or something. Would use the kangax compat-table. Important to note that it does not guarantee complete spec compliancy on the vendors end.</p>
<p dir="auto">References:</p>
<ul dir="auto">
<li><a href="https://github.com/kangax/compat-table">https://github.com/kangax/compat-table</a></li>
<li><a href="https://github.com/Fyrd/caniuse">https://github.com/Fyrd/caniuse</a></li>
<li><a href="https://github.com/3rd-Eden/useragent">https://github.com/3rd-Eden/useragent</a></li>
</ul>