React Warning: Unknown prop `valueAsNumber` on <input> tag
<p>I have a component that wraps an <code>&lt;input type=number&gt;</code>.</p>

<p>Here is my JSX:</p>

<pre><code>function InputNumber(props) {
    return (&lt;input
               type="number"
               valueAsNumber={props.value}
               onChange={e =&gt; props.onChange(e.target.valueAsNumber)}
               step={props.step}
    /&gt;);
}
</code></pre>

<p>This compiles to the following JS:</p>

<pre><code>function InputNumber(props) {
    return (React.createElement("input", {type: "number", valueAsNumber: props.value, onChange: function (e) { return props.onChange(e.target.valueAsNumber); }, step: props.step}));
}
</code></pre>

<p>React is giving me the following warning:</p>

<blockquote>
  <p>Warning: Unknown prop <code>valueAsNumber</code> on  tag. Remove this prop from the element.</p>
</blockquote>

<p>It seems to work fine if I read and write from <code>element.valueAsNumber</code> in the DOM, so why doesn't React know about this property?</p>