Data commit

Task/Ramer-Douglas-Peucker-line-simplification/JavaScript/ramer-douglas-peucker-line-simplification.js

@@ -0,0 +1,45 @@
+/**
+ * @typedef {{
+ *    x: (!number),
+ *    y: (!number)
+ * }}
+ */
+let pointType;
+
+/**
+ * @param {!Array<pointType>} l
+ * @param {number} eps
+ */
+const RDP = (l, eps) => {
+  const last = l.length - 1;
+  const p1 = l[0];
+  const p2 = l[last];
+  const x21 = p2.x - p1.x;
+  const y21 = p2.y - p1.y;
+
+  const [dMax, x] = l.slice(1, last)
+      .map(p => Math.abs(y21 * p.x - x21 * p.y + p2.x * p1.y - p2.y * p1.x))
+      .reduce((p, c, i) => {
+        const v = Math.max(p[0], c);
+        return [v, v === p[0] ? p[1] : i + 1];
+      }, [-1, 0]);
+
+  if (dMax > eps) {
+    return [...RDP(l.slice(0, x + 1), eps), ...RDP(l.slice(x), eps).slice(1)];
+  }
+  return [l[0], l[last]]
+};
+
+const points = [
+  {x: 0, y: 0},
+  {x: 1, y: 0.1},
+  {x: 2, y: -0.1},
+  {x: 3, y: 5},
+  {x: 4, y: 6},
+  {x: 5, y: 7},
+  {x: 6, y: 8.1},
+  {x: 7, y: 9},
+  {x: 8, y: 9},
+  {x: 9, y: 9}];
+
+console.log(RDP(points, 1));