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node_modules/vant/es/tabs/utils.js

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+import { raf } from '../utils/dom/raf';
+import { getScrollTop, setScrollTop } from '../utils/dom/scroll';
+export function scrollLeftTo(scroller, to, duration) {
+  var count = 0;
+  var from = scroller.scrollLeft;
+  var frames = duration === 0 ? 1 : Math.round(duration * 1000 / 16);
+
+  function animate() {
+    scroller.scrollLeft += (to - from) / frames;
+
+    if (++count < frames) {
+      raf(animate);
+    }
+  }
+
+  animate();
+}
+export function scrollTopTo(scroller, to, duration, callback) {
+  var current = getScrollTop(scroller);
+  var isDown = current < to;
+  var frames = duration === 0 ? 1 : Math.round(duration * 1000 / 16);
+  var step = (to - current) / frames;
+
+  function animate() {
+    current += step;
+
+    if (isDown && current > to || !isDown && current < to) {
+      current = to;
+    }
+
+    setScrollTop(scroller, current);
+
+    if (isDown && current < to || !isDown && current > to) {
+      raf(animate);
+    } else if (callback) {
+      raf(callback);
+    }
+  }
+
+  animate();
+}