feat(utils): add snapPosition function

packages/react/src/hooks/useGlobalKeyHandler.ts

@@ -6,7 +6,7 @@ import useKeyPress from './useKeyPress';
 import useReactFlow from './useReactFlow';
 import { Edge, Node } from '../types';
 
-const getSelected = (item: Node | Edge) => item.selected;
+const selected = (item: Node | Edge) => item.selected;
 
 export default ({
   deleteKeyCode,
@@ -24,7 +24,7 @@ export default ({
   useEffect(() => {
     if (deleteKeyPressed) {
       const { edges, nodes } = store.getState();
-      deleteElements({ nodes: nodes.filter(getSelected), edges: edges.filter(getSelected) });
+      deleteElements({ nodes: nodes.filter(selected), edges: edges.filter(selected) });
       store.setState({ nodesSelectionActive: false });
     }
   }, [deleteKeyPressed]);

packages/react/src/hooks/useResizeHandler.ts

@@ -3,18 +3,12 @@ import { errorMessages, getDimensions } from '@xyflow/system';
 
 import { useStoreApi } from '../hooks/useStore';
 
-function useResizeHandler(rendererNode: MutableRefObject<HTMLDivElement | null>): void {
+function useResizeHandler(domNode: MutableRefObject<HTMLDivElement | null>): void {
   const store = useStoreApi();
 
   useEffect(() => {
-    let resizeObserver: ResizeObserver;
-
     const updateDimensions = () => {
-      if (!rendererNode.current) {
-        return;
-      }
-
-      const size = getDimensions(rendererNode.current);
+      const size = getDimensions(domNode.current!);
 
       if (size.height === 0 || size.width === 0) {
         store.getState().onError?.('004', errorMessages['error004']());
@@ -23,21 +17,21 @@ function useResizeHandler(rendererNode: MutableRefObject<HTMLDivElement | null>)
       store.setState({ width: size.width || 500, height: size.height || 500 });
     };
 
-    updateDimensions();
-    window.addEventListener('resize', updateDimensions);
+    if (domNode.current) {
+      updateDimensions();
+      window.addEventListener('resize', updateDimensions);
 
-    if (rendererNode.current) {
-      resizeObserver = new ResizeObserver(() => updateDimensions());
-      resizeObserver.observe(rendererNode.current);
+      const resizeObserver = new ResizeObserver(() => updateDimensions());
+      resizeObserver.observe(domNode.current);
+
+      return () => {
+        window.removeEventListener('resize', updateDimensions);
+
+        if (resizeObserver && domNode.current) {
+          resizeObserver.unobserve(domNode.current);
+        }
+      };
     }
-
-    return () => {
-      window.removeEventListener('resize', updateDimensions);
-
-      if (resizeObserver && rendererNode.current) {
-        resizeObserver.unobserve(rendererNode.current!);
-      }
-    };
   }, []);
 }
 

packages/react/src/hooks/useUpdateNodePositions.ts

@@ -1,41 +1,49 @@
 import { useCallback } from 'react';
-import { calcNextPosition } from '@xyflow/system';
+import { calcNextPosition, snapPosition } from '@xyflow/system';
 
+import { Node } from '../types';
 import { useStoreApi } from '../hooks/useStore';
 
+const selectedAndDraggable = (nodesDraggable: boolean) => (n: Node) =>
+  n.selected && (n.draggable || (nodesDraggable && typeof n.draggable === 'undefined'));
+
 function useUpdateNodePositions() {
   const store = useStoreApi();
 
   const updatePositions = useCallback((params: { x: number; y: number; isShiftPressed: boolean }) => {
-    const { nodeExtent, updateNodePositions, nodes, snapToGrid, snapGrid, onError, nodesDraggable } = store.getState();
-    const selectedNodes = nodes.filter(
-      (n) => n.selected && (n.draggable || (nodesDraggable && typeof n.draggable === 'undefined'))
-    );
+    const { nodeExtent, nodes, snapToGrid, snapGrid, nodesDraggable, onError, updateNodePositions } = store.getState();
+    const selectedNodes = nodes.filter(selectedAndDraggable(nodesDraggable));
     // by default a node moves 5px on each key press, or 20px if shift is pressed
     // if snap grid is enabled, we use that for the velocity.
     const xVelo = snapToGrid ? snapGrid[0] : 5;
     const yVelo = snapToGrid ? snapGrid[1] : 5;
     const factor = params.isShiftPressed ? 4 : 1;
 
-    const positionDiffX = params.x * xVelo * factor;
-    const positionDiffY = params.y * yVelo * factor;
+    const xDiff = params.x * xVelo * factor;
+    const yDiff = params.y * yVelo * factor;
 
-    const nodeUpdates = selectedNodes.map((n) => {
-      if (n.positionAbsolute) {
-        const nextPosition = { x: n.positionAbsolute.x + positionDiffX, y: n.positionAbsolute.y + positionDiffY };
+    const nodeUpdates = selectedNodes.map((node) => {
+      if (node.positionAbsolute) {
+        let nextPosition = { x: node.positionAbsolute.x + xDiff, y: node.positionAbsolute.y + yDiff };
 
         if (snapToGrid) {
-          nextPosition.x = snapGrid[0] * Math.round(nextPosition.x / snapGrid[0]);
-          nextPosition.y = snapGrid[1] * Math.round(nextPosition.y / snapGrid[1]);
+          nextPosition = snapPosition(nextPosition, snapGrid);
         }
 
-        const { positionAbsolute, position } = calcNextPosition(n, nextPosition, nodes, nodeExtent, undefined, onError);
+        const { positionAbsolute, position } = calcNextPosition(
+          node,
+          nextPosition,
+          nodes,
+          nodeExtent,
+          undefined,
+          onError
+        );
 
-        n.position = position;
-        n.positionAbsolute = positionAbsolute;
+        node.position = position;
+        node.positionAbsolute = positionAbsolute;
       }
 
-      return n;
+      return node;
     });
 
     updateNodePositions(nodeUpdates, true, false);

packages/system/src/utils/graph.ts

@@ -144,21 +144,14 @@ export const pointToRendererPoint = (
   { x, y }: XYPosition,
   [tx, ty, tScale]: Transform,
   snapToGrid: boolean,
-  [snapX, snapY]: [number, number]
+  snapGrid: SnapGrid
 ): XYPosition => {
   const position: XYPosition = {
     x: (x - tx) / tScale,
     y: (y - ty) / tScale,
   };
 
-  if (snapToGrid) {
-    return {
-      x: snapX * Math.round(position.x / snapX),
-      y: snapY * Math.round(position.y / snapY),
-    };
-  }
-
-  return position;
+  return snapToGrid ? snapPosition(position, snapGrid) : position;
 };
 
 export const rendererPointToPoint = ({ x, y }: XYPosition, [tx, ty, tScale]: Transform): XYPosition => {
@@ -349,10 +342,12 @@ export function getPointerPosition(
     y: (y - transform[1]) / transform[2],
   };
 
+  const { x: xSnapped, y: ySnapped } = snapToGrid ? snapPosition(pointerPos, snapGrid) : pointerPos;
+
   // we need the snapped position in order to be able to skip unnecessary drag events
   return {
-    xSnapped: snapToGrid ? snapGrid[0] * Math.round(pointerPos.x / snapGrid[0]) : pointerPos.x,
-    ySnapped: snapToGrid ? snapGrid[1] * Math.round(pointerPos.y / snapGrid[1]) : pointerPos.y,
+    xSnapped,
+    ySnapped,
     ...pointerPos,
   };
 }
@@ -366,11 +361,11 @@ export function calcNextPosition<NodeType extends BaseNode>(
   onError?: OnError
 ): { position: XYPosition; positionAbsolute: XYPosition } {
   let currentExtent = node.extent || nodeExtent;
-  let parentNode: NodeType;
+  let parentNode: NodeType | null = null;
   let parentPos = { x: 0, y: 0 };
 
   if (node.parentNode) {
-    parentNode = nodes.find((n) => n.id === node.parentNode);
+    parentNode = nodes.find((n) => n.id === node.parentNode) || null;
     parentPos = parentNode
       ? getNodePositionWithOrigin(parentNode, parentNode.origin || nodeOrigin).positionAbsolute
       : parentPos;
@@ -413,3 +408,10 @@ export function calcNextPosition<NodeType extends BaseNode>(
     positionAbsolute,
   };
 }
+
+export function snapPosition(position: XYPosition, snapGrid: SnapGrid = [1, 1]) {
+  return {
+    x: snapGrid[0] * Math.round(position.x / snapGrid[0]),
+    y: snapGrid[1] * Math.round(position.y / snapGrid[1]),
+  };
+}

packages/system/src/xydrag/XYDrag.ts

@@ -1,7 +1,7 @@
 import { drag } from 'd3-drag';
 import { select } from 'd3-selection';
 
-import { calcAutoPan, getEventPosition, getPointerPosition, calcNextPosition } from '../utils';
+import { calcAutoPan, getEventPosition, getPointerPosition, calcNextPosition, snapPosition } from '../utils';
 import { getDragItems, getEventHandlerParams, hasSelector, wrapSelectionDragFunc } from './utils';
 import type {
   BaseNode,
@@ -107,11 +107,10 @@ export function XYDrag({
       let hasChange = false;
 
       dragItems = dragItems.map((n) => {
-        const nextPosition = { x: x - n.distance.x, y: y - n.distance.y };
+        let nextPosition = { x: x - n.distance.x, y: y - n.distance.y };
 
         if (snapToGrid) {
-          nextPosition.x = snapGrid[0] * Math.round(nextPosition.x / snapGrid[0]);
-          nextPosition.y = snapGrid[1] * Math.round(nextPosition.y / snapGrid[1]);
+          nextPosition = snapPosition(nextPosition, snapGrid);
         }
 
         const updatedPos = calcNextPosition(n, nextPosition, nodes, nodeExtent, nodeOrigin, onError);
@@ -173,10 +172,10 @@ export function XYDrag({
           transform,
           snapGrid,
           snapToGrid,
+          selectNodesOnDrag,
           onNodeDragStart,
           onSelectionDragStart,
           unselectNodesAndEdges,
-          selectNodesOnDrag,
         } = getStoreItems();
 
         if (!selectNodesOnDrag && !multiSelectionActive && nodeId) {