#84 : Validate autoplay duration value, add marquee demo

src/docs/Carousel.svx

@@ -129,6 +129,39 @@
 
 <Divider />
 
+## Marquee mode!anchorId:marquee-mode;
+<Carousel
+  autoplayDuration={0}
+  duration={5000}
+  autoplay
+  timingFunction="linear"
+  dots={false}
+  arrows={false}
+  swiping={false}
+>
+  {#each colors as { color, text } (color)}
+    <Color {color} {text} />
+  {/each}
+</Carousel>
+
+```jsx
+<Carousel
+  autoplayDuration={0}
+  duration={5000}
+  autoplay
+  timingFunction="linear"
+  dots={false}
+  arrows={false}
+  swiping={false}
+>
+  {#each colors as { color, text } (color)}
+    <Color {color} {text} />
+  {/each}
+</Carousel>
+```
+
+<Divider />
+
 ## Lazy loading of images!anchorId:features-lazy-loading;
 <Carousel
   let:loaded

src/utils/ProgressManager.js

@@ -22,7 +22,7 @@ export class ProgressManager {
     return new Promise((resolve) => {
       this.reset()
 
-      const stepMs = Math.min(STEP_MS, this._autoplayDuration)
+      const stepMs = Math.min(STEP_MS, Math.max(this._autoplayDuration, 1))
       let progress = -stepMs
   
       this._interval = setIntervalImmediate(async () => {