07Map $easings và mixin SCSS

<main class="stage is-demo">
  <div class="track">
    <span class="dot dot--start"></span>
    <span class="dot dot--end"></span>
    <div class="puck">S</div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;    // 2s
$easing: spring-snappy;  // 아래 $easings 맵의 키 — 값 자체가 아니라 "이름"을 변수로 넘긴다
$color: $subject-cream;

// 이 편 9종에 쓴 곡선을 이름으로 묶어두면, 편마다 값을 복붙하지 않고 이름만 불러 쓴다
$easings: (
  "ease-out-quart":    cubic-bezier(.25, 1, .5, 1),
  "ease-in-out-back":  cubic-bezier(.68, -.6, .32, 1.6),
  "spring-gentle":     linear(0, .044, .153, .297, .452, .602, .736, .849, .937, 1.002, 1.045, 1.071, 1.082, 1.083, 1.077, 1.066, 1.053, 1.04, 1.028, 1.018, 1.009, 1.003, 1),
  "spring-snappy":     linear(0, .055, .197, .394, .612, .824, 1.009, 1.153, 1.25, 1.3, 1.307, 1.281, 1.231, 1.167, 1.099, 1.035, .982, .942, .916, .905, .907, .917, .935, .955, .976, .995, 1),
);

@mixin ease($name, $prop: animation-timing-function) {
  #{$prop}: map.get($easings, $name);
}

@include stage($stage-orange);

$track-w: 220px;
$puck-w: $sp-8;
$travel: $track-w - $puck-w;

.track {
  position: relative;
  width: $track-w;
  height: $sp-2;
}

.dot {
  position: absolute;
  top: 50%;
  width: $sp-2;
  height: $sp-2;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .3);
  transform: translate(-50%, -50%);
}
.dot--start { left: 0; }
.dot--end { left: $track-w; }

.puck {
  position: absolute;
  top: 50%;
  left: 0;
  width: $puck-w;
  height: $puck-w;
  border-radius: $r-pill;
  background: $color;
  color: $stage-ink;
  font: 700 12px/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  display: grid;
  place-items: center;
  box-shadow: $shadow-raised;
  transform: translate(0, -50%);
}

.stage.is-demo .puck {
  animation-name: move;
  animation-duration: $duration;
  animation-iteration-count: infinite;
  animation-direction: alternate;
  @include ease($easing);   // ← 맵에서 spring-snappy 값을 꺼내 animation-timing-function 에 꽂는다
}

@keyframes move {
  from { transform: translate(0, -50%); }
  to   { transform: translate($travel, -50%); }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .puck { animation: none; transform: translate($travel, -50%); }
}

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);
}

.track {
  position: relative;
  width: 220px;
  height: 8px;
}

.dot {
  position: absolute;
  top: 50%;
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.3);
  transform: translate(-50%, -50%);
}

.dot--start {
  left: 0;
}

.dot--end {
  left: 220px;
}

.puck {
  position: absolute;
  top: 50%;
  left: 0;
  width: 32px;
  height: 32px;
  border-radius: 999px;
  background: #fff7e6;
  color: #17141a;
  font: 700 12px/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  display: grid;
  place-items: center;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform: translate(0, -50%);
}

.stage.is-demo .puck {
  animation-name: move;
  animation-duration: 2s;
  animation-iteration-count: infinite;
  animation-direction: alternate;
  animation-timing-function: linear(0, 0.055, 0.197, 0.394, 0.612, 0.824, 1.009, 1.153, 1.25, 1.3, 1.307, 1.281, 1.231, 1.167, 1.099, 1.035, 0.982, 0.942, 0.916, 0.905, 0.907, 0.917, 0.935, 0.955, 0.976, 0.995, 1);
}

@keyframes move {
  from {
    transform: translate(0, -50%);
  }
  to {
    transform: translate(188px, -50%);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .puck {
    animation: none;
    transform: translate(188px, -50%);
  }
}

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

// SCSS $easings 맵과 같은 값을 JS 객체로 옮겼다 — 이름으로 곡선을 찾는 패턴은 언어가 달라도 같다
const EASINGS = {
  "ease-out-quart": "cubic-bezier(.25, 1, .5, 1)",
  "ease-in-out-back": "cubic-bezier(.68, -.6, .32, 1.6)",
  "spring-gentle": "linear(0, .044, .153, .297, .452, .602, .736, .849, .937, 1.002, 1.045, 1.071, 1.082, 1.083, 1.077, 1.066, 1.053, 1.04, 1.028, 1.018, 1.009, 1.003, 1)",
  "spring-snappy": "linear(0, .055, .197, .394, .612, .824, 1.009, 1.153, 1.25, 1.3, 1.307, 1.281, 1.231, 1.167, 1.099, 1.035, .982, .942, .916, .905, .907, .917, .935, .955, .976, .995, 1)",
} as const;

export type EasingMapProps = {
  duration?: number;
  color?: string;
  /** 위 EASINGS 의 키. 기본은 SCSS 판과 같은 spring-snappy */
  easing?: keyof typeof EASINGS;
};

export default function EasingMap({ duration = 2000, color = "#fff7e6", easing = "spring-snappy" }: EasingMapProps) {
  const vars: CSSProperties = {
    "--duration": `${duration}ms`,
    "--color": color,
    "--ease": EASINGS[easing],
  } as CSSProperties;
  return (
    <div className={styles.stage} style={vars}>
      <div className={styles.track}>
        <span className={`${styles.dot} ${styles.dotStart}`} />
        <span className={`${styles.dot} ${styles.dotEnd}`} />
        <div className={styles.puck}>S</div>
      </div>
    </div>
  );
}