flow like the river

BACK_BACK/node_modules/d3-selection/src/pointer.js

@@ -0,0 +1,20 @@
+import sourceEvent from "./sourceEvent.js";
+
+export default function(event, node) {
+  event = sourceEvent(event);
+  if (node === undefined) node = event.currentTarget;
+  if (node) {
+    var svg = node.ownerSVGElement || node;
+    if (svg.createSVGPoint) {
+      var point = svg.createSVGPoint();
+      point.x = event.clientX, point.y = event.clientY;
+      point = point.matrixTransform(node.getScreenCTM().inverse());
+      return [point.x, point.y];
+    }
+    if (node.getBoundingClientRect) {
+      var rect = node.getBoundingClientRect();
+      return [event.clientX - rect.left - node.clientLeft, event.clientY - rect.top - node.clientTop];
+    }
+  }
+  return [event.pageX, event.pageY];
+}