Latest updates and announcements.

November 2023 - Toggle Group

We've added a new component to the library, Toggle Group.


October 2023 - New Components & Updates

We've added two new components to the library, Command & Combobox. We've also made some updates to the <Form.Label /> component that you'll want to be aware of.

New Component: Command

Command is a component that allows you to create a command palette. It's built on top of cmdk-sv, which is a Svelte port of cmdk. The library is still in its infancy, but we're excited to see where it goes. If you notice any issues, please open an issue with the library.


Be sure to check out the Command docs for more information.

New Component: Combobox

Combobox is a combination of the <Command /> & <Popover /> components. It allows you to create a searchable dropdown menu.


Be sure to check out the Combobox docs for more information.

Updates to Form

Form.Label Changes

Since we had to make some internal changes to formsnap to fix outstanding issues, there is a slight modification we have to make to the <Form.Label /> component. The ids returned from getFormField() is now a store, so we need to prefix it with $ when we use it.

  class={cn($errors && "text-destructive", className)}
  <slot />


Formsnap introduced a new component <Form.Control /> which wraps non-traditional form elements. This allows us to ensure the components are accessible, and work well with the rest of the form components. You'll need to define & export that control in your form/index.ts file.

const Control = FormPrimitive.Control;

export {
  Control as FormControl

August 2023 - Transitions & More


To support both enter and exit transitions, we've had to move from tailwindcss-animate to Svelte transitions. You can still use the tailwindcss-animate if you'd like, but you won't have exit transitions on most components.

To get the updated transition support, be sure to upgrade to the latest version of bits-ui, which at the time of this writing is 0.5.0.

We now provide a custom transition flyAndScale (thanks @thomasglopes) which most components use. It's added to the utils.ts file when you init a new project.


If you're using tailwindcss-animate and want to migrate to the new transition system, you'll need to do the following:

Update your utils.ts file to include the flyAndScale transition:

	import { type ClassValue, clsx } from "clsx";
import { twMerge } from "tailwind-merge";
import { cubicOut } from "svelte/easing";
import type { TransitionConfig } from "svelte/transition";

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs));

type FlyAndScaleParams = {
  y?: number;
  x?: number;
  start?: number;
  duration?: number;

export const flyAndScale = (
  node: Element,
  params: FlyAndScaleParams = { y: -8, x: 0, start: 0.95, duration: 150 }
): TransitionConfig => {
  const style = getComputedStyle(node);
  const transform = style.transform === "none" ? "" : style.transform;

  const scaleConversion = (
    valueA: number,
    scaleA: [number, number],
    scaleB: [number, number]
  ) => {
    const [minA, maxA] = scaleA;
    const [minB, maxB] = scaleB;

    const percentage = (valueA - minA) / (maxA - minA);
    const valueB = percentage * (maxB - minB) + minB;

    return valueB;

  const styleToString = (
    style: Record<string, number | string | undefined>
  ): string => {
    return Object.keys(style).reduce((str, key) => {
      if (style[key] === undefined) return str;
      return str + key + ":" + style[key] + ";";
    }, "");

  return {
    duration: params.duration ?? 200,
    delay: 0,
    css: (t) => {
      const y = scaleConversion(t, [0, 1], [params.y ?? 5, 0]);
      const x = scaleConversion(t, [0, 1], [params.x ?? 0, 0]);
      const scale = scaleConversion(t, [0, 1], [params.start ?? 0.95, 1]);

      return styleToString({
          transform +
          "translate3d(" +
          x +
          "px, " +
          y +
          "px, 0) scale(" +
          scale +
        opacity: t
    easing: cubicOut

Inside the components that use transitions/animations, you'll need to remove the animation classes and add the transition. Here's an example of the AlertDialog.Content component:

	<script lang="ts">
  import { AlertDialog as AlertDialogPrimitive } from "bits-ui";
  import * as AlertDialog from ".";
  import { cn, flyAndScale } from "$lib/utils";

  type $$Props = AlertDialogPrimitive.ContentProps;

  let className: $$Props["class"] = undefined;
  export let transition: $$Props["transition"] = flyAndScale;
  export let transitionConfig: $$Props["transitionConfig"] = undefined;
  export { className as class };

  <AlertDialog.Overlay />
      "fixed left-[50%] top-[50%] z-50 grid w-full max-w-lg translate-x-[-50%] translate-y-[-50%] gap-4 border bg-background p-6 shadow-lg  sm:rounded-lg md:w-full",
    <slot />

If you're unsure which specific classes should be removed, you can reference the components in the repo to see the changes.


Previous, we were using the same syntax as Melt UI for events, as we were simply forwarding them. So you'd have to do on:m-click or on:m-keydown. While this isn't a huge deal, since we're using components, we decided we wanted to use the same syntax as you would for any other Svelte component. So now you can just do on:click or on:keydown.

Behind the scenes, we're redispatching the event, so the contents of the event are the same, but the syntax is a bit more familiar.


To migrate to the new event syntax, you'll need to update your components that are forwarding the m- events. Ensure you're on the latest version of bits-ui before doing so.