<p dir="auto">I have following config in package.json:</p>
<div class="highlight highlight-source-json notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="...
&quot;babel&quot;: {
  &quot;optional&quot;: [
    &quot;runtime&quot;
  ]
},
..."><pre class="notranslate"><span class="pl-ii">...</span>
<span class="pl-ent">"babel"</span>: {
  <span class="pl-ent">"optional"</span>: [
    <span class="pl-s"><span class="pl-pds">"</span>runtime<span class="pl-pds">"</span></span>
  ]
},
<span class="pl-ii">...</span></pre></div>
<p dir="auto">which should add <code class="notranslate">Promise</code> and other classes. If I understand it correctly, it should also shim <code class="notranslate">Array.protoype functions</code>.</p>
<p dir="auto">Unfortunatelly, it does not work:</p>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="console.log(Promise) // Object
console.log(Array.prototype.find) // undefined
console.log(Array.find)) // Object"><pre class="notranslate"><span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-v">Promise</span><span class="pl-kos">)</span> <span class="pl-c">// Object</span>
<span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-v">Array</span><span class="pl-kos">.</span><span class="pl-c1">prototype</span><span class="pl-kos">.</span><span class="pl-c1">find</span><span class="pl-kos">)</span> <span class="pl-c">// undefined</span>
<span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-v">Array</span><span class="pl-kos">.</span><span class="pl-c1">find</span><span class="pl-kos">)</span><span class="pl-kos">)</span> <span class="pl-c">// Object</span></pre></div>
<p dir="auto">Why <code class="notranslate">Array.prototype.find</code> is undefined. Is there something what I missed? Thank you.</p>
<p dir="auto">When I call <code class="notranslate">[].find()</code> using <code class="notranslate">babel-node</code> it works, but it doesn't work in the runtime because it doesn't proxy <code class="notranslate">find</code> to <code class="notranslate">core-js</code>. Suggestion: use <code class="notranslate">_core.Array.find</code>, but this may be difficult. This probably belongs to a bigger class of problems regarding ES6 built-in prototype extensions. Easy way is to just polyfill it. Any ideas?</p>