03검색해서 좁히는 콤보박스

<main class="stage">
  <div class="cb is-demo">
    <span class="cb__label" id="cb-label">도시</span>
    <div class="cb__field">
      <span class="cb__mag" aria-hidden="true"><svg viewBox="0 0 256 256" width="13" height="13"><g fill="currentColor"><path d="M192 112a80 80 0 1 1-80-80a80 80 0 0 1 80 80" opacity=".2"/><path d="m229.66 218.34l-50.06-50.06a88.21 88.21 0 1 0-11.32 11.31l50.06 50.07a8 8 0 0 0 11.32-11.32M40 112a72 72 0 1 1 72 72a72.08 72.08 0 0 1-72-72"/></g></svg></span>
      <input class="cb__input" id="cb-input" type="text" role="combobox" aria-expanded="true" aria-controls="cb-list" aria-autocomplete="list" aria-labelledby="cb-label" placeholder="도시 검색" autocomplete="off">
      <span class="cb__typed" aria-hidden="true">대</span>
    </div>
    <div class="cb__box">
      <ul class="cb__list" id="cb-list" role="listbox" aria-labelledby="cb-label">
        <li class="cb__opt cb__opt--out" id="cb-o1" role="option" aria-selected="false">서울</li>
        <li class="cb__opt cb__opt--out" id="cb-o2" role="option" aria-selected="false">부산</li>
        <li class="cb__opt cb__opt--hit" id="cb-o3" role="option" aria-selected="false"><span class="cb__m">대</span>구</li>
        <li class="cb__opt cb__opt--hit" id="cb-o4" role="option" aria-selected="false"><span class="cb__m">대</span>전</li>
      </ul>
      <p class="cb__empty" id="cb-empty" hidden>검색 결과 없음</p>
    </div>
  </div>
</main>

@use "../../../../site/static/demo-tokens" as *;

$duration: $dur-quick;
$easing: $ease-spring;
$color: $subject-blue;

@include stage($stage-orange);

.cb {
  box-sizing: border-box;
  width: min(224px, 84vw);
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: $stage-ink;
}
.cb__label {
  display: block;
  font-size: 10px; line-height: 12px; font-weight: 800;
  letter-spacing: .04em;
  color: $subject-ink;
  margin: 0 0 $sp-1;
}
.cb__field {
  position: relative;
  box-sizing: border-box;
  height: 32px;
  display: flex; align-items: center; gap: $sp-2;
  padding: 0 $sp-3;
  background: #fff;
  border-radius: $r-control;
  box-shadow: $shadow-press;
}
.cb__mag { display: inline-flex; color: rgba(23, 20, 26, .4); }
.cb__input {
  flex: 1 1 auto;
  min-width: 0;
  border: 0; background: transparent;
  font-family: inherit;
  font-size: 12px; font-weight: 600;
  color: $stage-ink;
}
.cb__input:focus-visible { outline: 2px solid $color; outline-offset: 4px; border-radius: $r-xs; }
.cb__typed {
  position: absolute;
  left: 32px; right: 12px; top: 50%;
  display: flex; align-items: center;
  height: 18px;
  transform: translateY(-50%);
  background: #fff;
  font-size: 12px; font-weight: 700;
  color: $stage-ink;
  opacity: 0;
  pointer-events: none;
}

.cb__box {
  position: relative;
  box-sizing: border-box;
  height: 104px;
  margin: $sp-2 0 0;
  padding: $sp-1;
  overflow: hidden;
  background: #fff;
  border-radius: $r-card;
  box-shadow: $shadow-press;
}
.cb__list { margin: 0; padding: 0; list-style: none; }
.cb__opt {
  box-sizing: border-box;
  height: 24px;
  display: flex; align-items: center;
  padding: 0 $sp-2;
  border-radius: $r-sm;
  font-size: 12px; font-weight: 600;
  color: rgba(23, 20, 26, .78);
  cursor: pointer;
}
.cb__opt.is-at { background: rgba(47, 109, 246, .12); color: $color; }
.cb__m { position: relative; z-index: 0; font-weight: 800; }
.cb__m::before {
  content: "";
  position: absolute;
  inset: -2px -2px;
  z-index: -1;
  border-radius: $r-xs;
  background: rgba(255, 201, 77, .8);
  opacity: 0;
}
.cb__m.is-on::before { opacity: 1; }
.cb__empty {
  margin: 0; padding: $sp-2;
  font-size: 11px; font-weight: 600;
  color: rgba(23, 20, 26, .4);
}

// ── 자동 루프: 「대」를 치면 안 맞는 두 줄이 사라지고 맞은 두 줄이 올라온다. 다시 원래대로 되돌아온다 ──
// 사라지는 줄과 올라오는 줄이 같은 자리를 지나므로, 사라짐은 steps(1) 로 먼저 끝내고
// 그다음 남은 줄이 미끄러져 올라온다 — 겹쳐 비치는 프레임이 없다
.cb.is-demo .cb__typed,
.cb.is-demo .cb__m::before { animation: cb-cut-in $dur-loop steps(1, end) infinite; }
.cb.is-demo .cb__opt--out { animation: cb-cut-out $dur-loop steps(1, end) infinite; }
.cb.is-demo .cb__opt--hit { animation: cb-rise $dur-loop $easing infinite; }
@keyframes cb-cut-in {
  0%, 17%   { opacity: 0; }
  18%, 83%  { opacity: 1; }
  84%, 100% { opacity: 0; }
}
@keyframes cb-cut-out {
  0%, 17%   { opacity: 1; }
  18%, 83%  { opacity: 0; }
  84%, 100% { opacity: 1; }
}
@keyframes cb-rise {
  0%, 18%   { transform: translateY(0); }
  40%, 62%  { transform: translateY(-48px); }
  84%, 100% { transform: translateY(0); }
}

@media (prefers-reduced-motion: reduce) {
  .cb.is-demo .cb__typed,
  .cb.is-demo .cb__opt--out,
  .cb.is-demo .cb__opt--hit,
  .cb.is-demo .cb__m::before { animation: none !important; }
  .cb__typed { opacity: 0; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.cb {
  box-sizing: border-box;
  width: min(224px, 84vw);
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: #17141a;
}

.cb__label {
  display: block;
  font-size: 10px;
  line-height: 12px;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: #17141a;
  margin: 0 0 4px;
}

.cb__field {
  position: relative;
  box-sizing: border-box;
  height: 32px;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0 12px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.cb__mag {
  display: inline-flex;
  color: rgba(23, 20, 26, 0.4);
}

.cb__input {
  flex: 1 1 auto;
  min-width: 0;
  border: 0;
  background: transparent;
  font-family: inherit;
  font-size: 12px;
  font-weight: 600;
  color: #17141a;
}

.cb__input:focus-visible {
  outline: 2px solid #2f6df6;
  outline-offset: 4px;
  border-radius: 4px;
}

.cb__typed {
  position: absolute;
  left: 32px;
  right: 12px;
  top: 50%;
  display: flex;
  align-items: center;
  height: 18px;
  transform: translateY(-50%);
  background: #fff;
  font-size: 12px;
  font-weight: 700;
  color: #17141a;
  opacity: 0;
  pointer-events: none;
}

.cb__box {
  position: relative;
  box-sizing: border-box;
  height: 104px;
  margin: 8px 0 0;
  padding: 4px;
  overflow: hidden;
  background: #fff;
  border-radius: 16px;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.cb__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.cb__opt {
  box-sizing: border-box;
  height: 24px;
  display: flex;
  align-items: center;
  padding: 0 8px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 600;
  color: rgba(23, 20, 26, 0.78);
  cursor: pointer;
}

.cb__opt.is-at {
  background: rgba(47, 109, 246, 0.12);
  color: #2f6df6;
}

.cb__m {
  position: relative;
  z-index: 0;
  font-weight: 800;
}

.cb__m::before {
  content: "";
  position: absolute;
  inset: -2px -2px;
  z-index: -1;
  border-radius: 4px;
  background: rgba(255, 201, 77, 0.8);
  opacity: 0;
}

.cb__m.is-on::before {
  opacity: 1;
}

.cb__empty {
  margin: 0;
  padding: 8px;
  font-size: 11px;
  font-weight: 600;
  color: rgba(23, 20, 26, 0.4);
}

.cb.is-demo .cb__typed,
.cb.is-demo .cb__m::before {
  animation: cb-cut-in 2s steps(1, end) infinite;
}

.cb.is-demo .cb__opt--out {
  animation: cb-cut-out 2s steps(1, end) infinite;
}

.cb.is-demo .cb__opt--hit {
  animation: cb-rise 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes cb-cut-in {
  0%, 17% {
    opacity: 0;
  }
  18%, 83% {
    opacity: 1;
  }
  84%, 100% {
    opacity: 0;
  }
}
@keyframes cb-cut-out {
  0%, 17% {
    opacity: 1;
  }
  18%, 83% {
    opacity: 0;
  }
  84%, 100% {
    opacity: 1;
  }
}
@keyframes cb-rise {
  0%, 18% {
    transform: translateY(0);
  }
  40%, 62% {
    transform: translateY(-48px);
  }
  84%, 100% {
    transform: translateY(0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .cb.is-demo .cb__typed,
  .cb.is-demo .cb__opt--out,
  .cb.is-demo .cb__opt--hit,
  .cb.is-demo .cb__m::before {
    animation: none !important;
  }
  .cb__typed {
    opacity: 0;
  }
}

// 실제 동작: 글자를 치면 목록이 실제로 줄고, 맞은 글자만 형광으로 칠해진다.
var root = document.querySelector('.cb');
var input = document.getElementById('cb-input');
var list = document.getElementById('cb-list');
var empty = document.getElementById('cb-empty');
var opts = [].slice.call(list.querySelectorAll('.cb__opt'));
var names = opts.map(function (o) { return o.textContent; });
var at = -1;
function render(q) {
  root.classList.remove('is-demo');
  var shown = 0;
  opts.forEach(function (o, i) {
    var hit = !q || names[i].indexOf(q) >= 0;
    o.hidden = !hit;
    if (hit) {
      shown++;
      var k = names[i].indexOf(q);
      o.innerHTML = !q ? names[i]
        : names[i].slice(0, k) + '<span class="cb__m is-on">' + q + '</span>' + names[i].slice(k + q.length);
    }
  });
  empty.hidden = shown > 0;
  at = -1;
}
input.addEventListener('input', function () { render(input.value.trim()); });
input.addEventListener('keydown', function (e) {
  var vis = opts.filter(function (o) { return !o.hidden; });
  if (e.key === 'ArrowDown' || e.key === 'ArrowUp') {
    at = Math.max(0, Math.min(at + (e.key === 'ArrowDown' ? 1 : -1), vis.length - 1));
    vis.forEach(function (o, i) { o.classList.toggle('is-at', i === at); });
    if (vis[at]) input.setAttribute('aria-activedescendant', vis[at].id);
    e.preventDefault();
  } else if (e.key === 'Enter' && vis[at]) {
    vis.forEach(function (o) { o.setAttribute('aria-selected', String(o === vis[at])); });
    input.value = vis[at].textContent;
    render('');
    e.preventDefault();
  } else if (e.key === 'Escape') {
    input.value = ''; render(''); input.focus({ preventScroll: true });
  }
});

import { useRef, useState } from "react";
import type { CSSProperties } from "react";
import styles from "./SearchCombobox.module.scss";

export type SearchComboboxProps = {
  label?: string;
  placeholder?: string;
  emptyText?: string;
  options?: string[];
  duration?: number;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type KeyEvt = { key: string; preventDefault: () => void };
type ChangeEvt = { target: { value: string } };
type ClickEvt = { stopPropagation: () => void };

type Slice = { before: string; hit: string; after: string };

function split(name: string, q: string): Slice {
  if (!q) return { before: name, hit: "", after: "" };
  const k = name.toLowerCase().indexOf(q.toLowerCase());
  if (k < 0) return { before: name, hit: "", after: "" };
  return { before: name.slice(0, k), hit: name.slice(k, k + q.length), after: name.slice(k + q.length) };
}

export default function SearchCombobox({
  label = "City",
  placeholder = "Search city",
  emptyText = "No results",
  options = ["Seoul", "Busan", "Daegu", "Daejeon"],
  duration = 220,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#2f6df6",
}: SearchComboboxProps) {
  const [query, setQuery] = useState("");
  const [filter, setFilter] = useState("");
  const [picked, setPicked] = useState<string | null>(null);
  const [at, setAt] = useState(-1);
  const inputRef = useRef<HTMLInputElement>(null);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  const visible = options
    .map((name, i) => ({ name, i }))
    .filter(({ name }) => !filter || name.toLowerCase().includes(filter.toLowerCase()));

  function choose(name: string) {
    setPicked(name);
    setQuery(name);
    setFilter("");
    setAt(-1);
  }

  return (
    <div className={styles.cb} style={vars}>
      <span className={styles.label} id="cb-label">{label}</span>
      <div className={styles.field}>
        <span className={styles.mag} aria-hidden="true">
          <svg viewBox="0 0 256 256" width="13" height="13">
            <g fill="currentColor">
              <path d="M192 112a80 80 0 1 1-80-80a80 80 0 0 1 80 80" opacity=".2" />
              <path d="m229.66 218.34l-50.06-50.06a88.21 88.21 0 1 0-11.32 11.31l50.06 50.07a8 8 0 0 0 11.32-11.32M40 112a72 72 0 1 1 72 72a72.08 72.08 0 0 1-72-72" />
            </g>
          </svg>
        </span>
        <input
          ref={inputRef}
          id="cb-input"
          className={styles.input}
          type="text"
          role="combobox"
          aria-expanded="true"
          aria-controls="cb-list"
          aria-autocomplete="list"
          aria-labelledby="cb-label"
          aria-activedescendant={at >= 0 && visible[at] ? `cb-o${visible[at].i}` : undefined}
          placeholder={placeholder}
          autoComplete="off"
          value={query}
          onChange={(e: ChangeEvt) => {
            const q = e.target.value;
            setQuery(q);
            setFilter(q.trim());
            setAt(-1);
          }}
          onKeyDown={(e: KeyEvt) => {
            if (e.key === "ArrowDown" || e.key === "ArrowUp") {
              setAt((a) => Math.max(0, Math.min(a + (e.key === "ArrowDown" ? 1 : -1), visible.length - 1)));
              e.preventDefault();
            } else if (e.key === "Enter" && visible[at]) {
              choose(visible[at].name);
              e.preventDefault();
            } else if (e.key === "Escape") {
              setQuery("");
              setFilter("");
              setAt(-1);
              inputRef.current?.focus({ preventScroll: true });
            }
          }}
        />
      </div>
      <div className={styles.box}>
        <ul id="cb-list" className={styles.list} role="listbox" aria-labelledby="cb-label">
          {visible.map(({ name, i }, vi) => {
            const s = split(name, filter);
            return (
              <li
                key={name}
                id={`cb-o${i}`}
                className={`${styles.opt} ${vi === at ? styles.isAt : ""}`}
                role="option"
                aria-selected={name === picked}
                onMouseMove={() => setAt(vi)}
                onClick={() => choose(name)}
              >
                {s.before}
                {s.hit ? <mark className={styles.mark}>{s.hit}</mark> : null}
                {s.after}
              </li>
            );
          })}
        </ul>
        {visible.length === 0 ? <p className={styles.empty} id="cb-empty">{emptyText}</p> : null}
      </div>
    </div>
  );
}