The host element is used to mark the component boundaries. Without the host element, Qwik would not know where components start and end. This information is needed so that components can render independently and out of order, a key feature of Qwik.
An alternative to the host element is to recover the component boundaries by re-executing the application as part of hydration. Qwik's explicit goal is to not perform hydration on application startup as it would force eager application download and execution and negatively impact startup performance.
Controlling the Host Element Type with tagName
Every component declared with component$() has a host element. At times it may be necessary to change the <div> to another element, in which case the tagName option can be used with component$() as shown in this example.
<Host> Element
A component may need to add additional attributes or listeners to the host element. This can be done through the <Host> element. Any attribute that can be placed on the DOM element can be placed on the <Host>.
Example
In this example, we have created <MyButton> component. This component needs to be a <button> for accessibility. The example uses tagName to ensure that the host element is button.
We need to place a click listener on the button, for this, we use <Host> element to refer to the host element.
Please add styling to the <button> to change the background-color to lightpink and make the button large by adding padding to it.