svelte/documentation/docs/05-special-elements/06-svelte-options.md

title
<svelte:options>

<svelte:options option={value} />

The <svelte:options> element provides a place to specify per-component compiler options, which are detailed in the compiler section. The possible options 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
• accessors={true} — adds getters and setters for the component's props
• accessors={false} — the default
• runes={true} — forces a component into runes mode (see the Legacy APIs section)
• runes={false} — forces a component into legacy mode
• namespace="..." — the namespace where this component will be used, most commonly "svg"; use the "foreign" namespace to opt out of case-insensitive attribute names and HTML-specific warnings
• customElement={...} — the options to use when compiling this component as a custom element. If a string is passed, it is used as the tag option

<svelte:options customElement="my-custom-element" />