svelte/site/content/tutorial/16-special-elements/07-svelte-options/text.md

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<svelte:options>

Lastly, <svelte:options> allows you to specify compiler options.

Here, we have a component inside an <svg> element. Unless we tell Svelte otherwise, it will compile Square.svelte to a module that generates HTML nodes instead of SVG nodes. We can correct that by adding this to the top of Square.svelte:

<svelte:options namespace="svg"/>

The options that can be set here are:

• immutable={true} — you never use mutable data, so the compiler can do simple referential equality checks to determine if values have changed
• immutable={false} — the default. Svelte will be more conservative about whether or not mutable objects have changed
• namespace="..." — the namespace where this component will be used, most commonly "svg"
• tag="..." — the name to use when compiling this component as a custom element

Consult the API reference for more information on these options.