02Keys present in one locale only

Key rows on both columns light up and fill in sequence, but the missing one stays dark while a red defect mark pops in to point at the gap.

Best forWhen a button comes back empty on the English page, or a new key was only added to Korean

animation-delay: calc()차집합Set

<main class="stage is-demo">
  <div class="board">
    <div class="col">
      <p class="col__head">ko</p>
      <ul class="col__rows">
        <li class="pill" style="--i:0">nav.home</li>
        <li class="pill" style="--i:1">nav.about</li>
        <li class="pill" style="--i:2">nav.cart</li>
        <li class="pill" style="--i:3">nav.mypage</li>
      </ul>
    </div>
    <div class="col">
      <p class="col__head">en</p>
      <ul class="col__rows">
        <li class="pill pill--en" style="--i:0">nav.home</li>
        <li class="pill pill--en" style="--i:1">nav.about</li>
        <li class="pill pill--en" style="--i:2">nav.cart</li>
        <li class="slot" style="--i:3"><span class="slot__badge">missing</span></li>
      </ul>
    </div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;      // 2s — 칸 채우기 한 주기
$easing: $ease-pop;
$color: $subject-ink;      // ko 알약

@include stage($stage-yellow);

.board {
  width: min(400px, 92vw);
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: $sp-4;
}

.col__head {
  margin: 0 0 $sp-2;
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: clamp(12px, 2.8vw, 15px);
  font-weight: 700;
  color: $subject-ink;
  text-align: center;
}

.col__rows {
  list-style: none;
  margin: 0; padding: 0;
  display: grid;
  row-gap: $sp-2;
}

.pill, .slot {
  border-radius: $r-control;
  min-height: clamp(24px, 8vw, 34px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: clamp(9.5px, 2.3vw, 13px);
  font-weight: 700;
}

.pill { background: $color; color: $stage-yellow; box-shadow: $shadow-press; }
.pill--en { background: $subject-cream; color: $subject-ink; }

.slot {
  position: relative;
  border: 2px dashed rgba($error, .65);
}

.slot__badge {
  border-radius: $r-pill;
  background: $error;
  color: #fff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-size: clamp(10px, 2.4vw, 13px);
  font-weight: 800;
  padding: $sp-1 $sp-2;
}

// 칸이 하나씩 채워진다 — ko 가 반 박자 앞선다
.stage.is-demo .pill { animation: fill-in $duration $easing infinite; animation-delay: calc(var(--i) * .16s); }
.stage.is-demo .pill--en { animation-delay: calc(var(--i) * .16s + .24s); }
.stage.is-demo .slot { animation: slot-alarm $duration $ease-out infinite; animation-delay: calc(var(--i) * .16s + .24s); }
.stage.is-demo .slot__badge { animation: badge-pop $duration $easing infinite; animation-delay: calc(var(--i) * .16s + .3s); }

@keyframes fill-in {
  0%       { transform: scale(0); opacity: 0; }
  9%       { transform: scale(1.12); opacity: 1; }
  14%, 92% { transform: scale(1); opacity: 1; }
  100%     { transform: scale(.7); opacity: 0; }
}
@keyframes slot-alarm {
  0%, 12%  { background: transparent; }
  20%      { background: rgba($error, .28); }
  28%      { background: rgba($error, .08); }
  36%      { background: rgba($error, .28); }
  44%, 96% { background: rgba($error, .20); }
  100%     { background: transparent; }
}
@keyframes badge-pop {
  0%, 12%  { transform: scale(0) rotate(0deg); opacity: 0; }
  20%      { transform: scale(1.25) rotate(0deg); opacity: 1; }
  26%      { transform: scale(1) rotate(0deg); }
  36%      { transform: scale(1) rotate(8deg); }
  44%      { transform: scale(1) rotate(-8deg); }
  52%      { transform: scale(1) rotate(4deg); }
  58%, 94% { transform: scale(1) rotate(0deg); opacity: 1; }
  100%     { transform: scale(.5); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .pill,
  .stage.is-demo .slot,
  .stage.is-demo .slot__badge { animation: none; }
  .slot { background: rgba($error, .20); }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.board {
  width: min(400px, 92vw);
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: 16px;
}

.col__head {
  margin: 0 0 8px;
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: clamp(12px, 2.8vw, 15px);
  font-weight: 700;
  color: #17141a;
  text-align: center;
}

.col__rows {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  row-gap: 8px;
}

.pill, .slot {
  border-radius: 12px;
  min-height: clamp(24px, 8vw, 34px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: clamp(9.5px, 2.3vw, 13px);
  font-weight: 700;
}

.pill {
  background: #17141a;
  color: #ffd23f;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.pill--en {
  background: #fff7e6;
  color: #17141a;
}

.slot {
  position: relative;
  border: 2px dashed rgba(194, 54, 26, 0.65);
}

.slot__badge {
  border-radius: 999px;
  background: #c2361a;
  color: #fff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-size: clamp(10px, 2.4vw, 13px);
  font-weight: 800;
  padding: 4px 8px;
}

.stage.is-demo .pill {
  animation: fill-in 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
  animation-delay: calc(var(--i) * 0.16s);
}

.stage.is-demo .pill--en {
  animation-delay: calc(var(--i) * 0.16s + 0.24s);
}

.stage.is-demo .slot {
  animation: slot-alarm 2s ease-out infinite;
  animation-delay: calc(var(--i) * 0.16s + 0.24s);
}

.stage.is-demo .slot__badge {
  animation: badge-pop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
  animation-delay: calc(var(--i) * 0.16s + 0.3s);
}

@keyframes fill-in {
  0% {
    transform: scale(0);
    opacity: 0;
  }
  9% {
    transform: scale(1.12);
    opacity: 1;
  }
  14%, 92% {
    transform: scale(1);
    opacity: 1;
  }
  100% {
    transform: scale(0.7);
    opacity: 0;
  }
}
@keyframes slot-alarm {
  0%, 12% {
    background: transparent;
  }
  20% {
    background: rgba(194, 54, 26, 0.28);
  }
  28% {
    background: rgba(194, 54, 26, 0.08);
  }
  36% {
    background: rgba(194, 54, 26, 0.28);
  }
  44%, 96% {
    background: rgba(194, 54, 26, 0.2);
  }
  100% {
    background: transparent;
  }
}
@keyframes badge-pop {
  0%, 12% {
    transform: scale(0) rotate(0deg);
    opacity: 0;
  }
  20% {
    transform: scale(1.25) rotate(0deg);
    opacity: 1;
  }
  26% {
    transform: scale(1) rotate(0deg);
  }
  36% {
    transform: scale(1) rotate(8deg);
  }
  44% {
    transform: scale(1) rotate(-8deg);
  }
  52% {
    transform: scale(1) rotate(4deg);
  }
  58%, 94% {
    transform: scale(1) rotate(0deg);
    opacity: 1;
  }
  100% {
    transform: scale(0.5);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .pill,
  .stage.is-demo .slot,
  .stage.is-demo .slot__badge {
    animation: none;
  }
  .slot {
    background: rgba(194, 54, 26, 0.2);
  }
}

import type { CSSProperties } from "react";
import styles from "./MissingKeyCheck.module.scss";

export type MissingKeyCheckProps = {
  duration?: number;
  easing?: string;
  color?: string;
  badge?: string;
};

const KO_KEYS = ["nav.home", "nav.about", "nav.cart", "nav.mypage"];
const EN_KEYS = ["nav.home", "nav.about", "nav.cart"];

export default function MissingKeyCheck({
  duration = 2000,
  easing = "cubic-bezier(.2, 1.4, .4, 1)",
  color = "#17141a",
  badge = "누락",
}: MissingKeyCheckProps) {
  const vars: CSSProperties = { "--duration": `${duration}ms`, "--easing": easing, "--color": color } as CSSProperties;
  return (
    <div className={styles.stage} style={vars} aria-label="한쪽 언어에만 있는 키 데모" role="img">
      <div className={styles.board}>
        <div className={styles.col}>
          <p className={styles.head}>ko</p>
          <ul className={styles.rows}>
            {KO_KEYS.map((k, i) => (
              <li key={k} className={styles.pill} style={{ "--i": i } as CSSProperties}>{k}</li>
            ))}
          </ul>
        </div>
        <div className={styles.col}>
          <p className={styles.head}>en</p>
          <ul className={styles.rows}>
            {EN_KEYS.map((k, i) => (
              <li key={k} className={`${styles.pill} ${styles.pillEn}`} style={{ "--i": i } as CSSProperties}>{k}</li>
            ))}
            <li className={styles.slot} style={{ "--i": 3 } as CSSProperties}>
              <span className={styles.badge}>{badge}</span>
            </li>
          </ul>
        </div>
      </div>
    </div>
  );
}

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02 Keys present in one locale only — Measured area 52.565% · moving frames 21/23Original by GODRICH · SCSS and React ship in the zip · i18n JSON Checks: 9 Ways to Catch Missing Keys

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i18n JSON Checks: 9 Ways to Catch Missing Keys - preview of all 9 demos

i18n JSON Checks: 9 Ways to Catch Missing Keysi18n JSON files break quietly: a key missing from en.json leaves a button empty, and a stray {name} placeholder ships wi See all demos in this post

02Keys present in one locale only

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