Input OTP

Use the inputOTP 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.

inputOTP

import type { PartialElement } from "@domphy/core";
import { themeSpacing } from "@domphy/theme";

/**
 * Lays out a one-time-password container as a horizontal row of inputs and
 * wires keyboard navigation: auto-advance on input, backspace/arrow movement,
 * and paste distribution across the child inputs. Apply to a container element
 * (e.g. `<div>`) whose direct children are the OTP `<input>` boxes. Takes no
 * props.
 *
 * @example { div: null, $: [inputOTP()], children: [{ input: null }, { input: null }] }
 */
function inputOTP(): PartialElement {
  return {
    style: {
      display: "flex",
      alignItems: "center",
      gap: themeSpacing(2),
      "& > *": {
        minWidth: `${themeSpacing(9)}!important`,
      },
    },
    _onMount: (node) => {
      const container = node.domElement as HTMLElement;
      const getInputs = () =>
        Array.from(container.querySelectorAll("input")) as HTMLInputElement[];

      const onInput = (e: Event) => {
        const inputs = getInputs();
        const target = e.target as HTMLInputElement;
        const idx = inputs.indexOf(target);
        if (target.value && idx < inputs.length - 1) {
          inputs[idx + 1].focus();
        }
      };

      const onKeydown = (e: KeyboardEvent) => {
        const inputs = getInputs();
        const target = e.target as HTMLInputElement;
        const idx = inputs.indexOf(target);
        if (e.key === "Backspace" && !target.value && idx > 0) {
          inputs[idx - 1].focus();
        }
        if (e.key === "ArrowLeft" && idx > 0) inputs[idx - 1].focus();
        if (e.key === "ArrowRight" && idx < inputs.length - 1)
          inputs[idx + 1].focus();
      };

      const onPaste = (e: ClipboardEvent) => {
        e.preventDefault();
        const text = e.clipboardData?.getData("text") ?? "";
        const inputs = getInputs();
        const startIdx = inputs.indexOf(e.target as HTMLInputElement);
        [...text].forEach((char, i) => {
          if (inputs[startIdx + i]) inputs[startIdx + i].value = char;
        });
        const lastFilled = Math.min(
          startIdx + text.length - 1,
          inputs.length - 1,
        );
        inputs[lastFilled]?.focus();
      };

      container.addEventListener("input", onInput);
      container.addEventListener("keydown", onKeydown as EventListener);
      container.addEventListener("paste", onPaste as EventListener);

      node.addHook("Remove", () => {
        container.removeEventListener("input", onInput);
        container.removeEventListener("keydown", onKeydown as EventListener);
        container.removeEventListener("paste", onPaste as EventListener);
      });
    },
  };
}

export { inputOTP };

</div>