Toast

Use the toast patch to customize this element.

Customization

Must see the source of patch at the bottom of each patch page to understand the structure then code it still code as html native element.

There are four levels of customization, in increasing order of effort:

Patch props. Each patch exposes a small, stable set of props—typically fewer than five. Lowest friction.
Context attributes. Use dataTone, dataSize, and dataDensity on a container to shift tone, size, or density for an entire subtree without touching individual elements.
Inline override. Native-wins merge strategy: any property set directly on the element overrides the patch value.
Create a variant. Clone a similar patch and edit it. Use this only when you need a reusable custom version.

Formulas

Unit - U = fontSize / 4 - convert final values with themeSpacing(n).

Size - n = intrinsic text lines, w = wrapping level, d = density factor:

height        = (n * 6 + 2 * d * w) * U
paddingBlock  = d * w * U
paddingInline = ceil(3 / w) * d * w * U
radius        = d * w * U

Base density d = 1.5:

U	w=0	w=1	w=2	w=3
height (`n = 1`)	6	9	12	15
paddingBlock	0	1.5	3	4.5
paddingInline	3	4.5	6	4.5
radius	0	1.5	3	4.5

Tone - K = N / 2 where N is the palette length. For N = 18, K = 9.

Role	Shift	n=0
Background	parent +/- n	0
Text	bg + K	6
Border	bg + K/2	3
Hover	bg + 2K/3	4
Selected / Focus	above +/- K/3	2-4

State shift range: K/3 <= delta <= 2K/3.

toast

import type { DomphyElement, ElementNode, PartialElement } from "@domphy/core";
import { toState } from "@domphy/core";
import {
  type ThemeColor,
  themeColor,
  themeDensity,
  themeSize,
  themeSpacing,
} from "@domphy/theme";

type ToastPosition =
  | "top-left"
  | "top-center"
  | "top-right"
  | "bottom-left"
  | "bottom-center"
  | "bottom-right";

/**
 * Renders a transient notification surface as a fixed-position overlay (portaled
 * into a corner stack), animating in on mount and out before removal. No host
 * tag check; typically applied to a `<div>`.
 *
 * @param props.position - Corner of the screen for the toast stack. Optional, one of `"top-left" | "top-center" | "top-right" | "bottom-left" | "bottom-center" | "bottom-right"`. Defaults to `"top-center"`.
 * @param props.color - Theme color for the toast surface. Optional. Defaults to `"neutral"`.
 * @example { div: "Saved!", $: [toast({ position: "top-right" })] }
 */
function toast(
  props: { position?: ToastPosition; color?: ThemeColor } = {},
): PartialElement {
  const { position = "top-center", color = "neutral" } = props;
  const state = toState(false);

  const isTop = position.startsWith("top");
  const isCenter = position.endsWith("center");
  const isRight = position.endsWith("right");

  const overlayEle: DomphyElement<"div"> = {
    div: [],
    id: `domphy-toast-${position}`,
    style: {
      position: "fixed",
      display: "flex",
      flexDirection: isTop ? "column" : "column-reverse",
      alignItems: isCenter ? "center" : isRight ? "end" : "start",
      inset: 0,
      gap: themeSpacing(4),
      zIndex: 30,
      padding: themeSpacing(6),
      pointerEvents: "none",
    },
  };

  return {
    _portal: (rootNode) => {
      let overlay = rootNode.domElement!.querySelector(
        `#domphy-toast-${position}`,
      );
      if (!overlay) {
        const overlayNode = rootNode.children!.insert(
          overlayEle,
        ) as ElementNode;
        overlay = overlayNode.domElement!;
      }
      return overlay;
    },
    role: "status",
    ariaAtomic: "true",
    // Toast is rendered as an overlay surface, so it uses the inverted branch.
    dataTone: "shift-17",
    style: {
      minWidth: themeSpacing(32),
      pointerEvents: "auto",
      paddingBlock: (listener) => themeSpacing(themeDensity(listener) * 2),
      paddingInline: (listener) => themeSpacing(themeDensity(listener) * 4),
      borderRadius: (listener) => themeSpacing(themeDensity(listener) * 2),
      fontSize: (listener) => themeSize(listener, "inherit"),
      color: (listener) => themeColor(listener, "shift-9", color),
      backgroundColor: (listener) => themeColor(listener, "inherit", color),
      boxShadow: (listener) =>
        `0 ${themeSpacing(2)} ${themeSpacing(9)} ${themeColor(listener, "shift-4", "neutral")}`,
      opacity: (listener) => Number(state.get(listener)),
      transform: (listener) =>
        state.get(listener)
          ? "translateY(0)"
          : isTop
            ? "translateY(-100%)"
            : "translateY(100%)",
      transition: "opacity 300ms ease, transform 300ms ease",
    },
    _onMount: () => requestAnimationFrame(() => state.set(true)),
    _onBeforeRemove: (node, done) => {
      const onEnd = (e: Event) => {
        if ((e as TransitionEvent).propertyName === "transform") {
          node.domElement!.removeEventListener("transitionend", onEnd);
          done();
        }
      };
      node.domElement!.addEventListener("transitionend", onEnd);
      state.set(false);
    },
  };
}

export { toast };

</div>