1 files changed, 102 insertions, 0 deletions
diff --git a/packages/excalidraw/element/elementLink.ts b/packages/excalidraw/element/elementLink.ts
new file mode 100644
index 0000000..991f9ca
--- /dev/null
+++ b/packages/excalidraw/element/elementLink.ts
@@ -0,0 +1,102 @@
+/**
+ * Create and link between shapes.
+ */
+
+import { ELEMENT_LINK_KEY } from "../constants";
+import { normalizeLink } from "../data/url";
+import { elementsAreInSameGroup } from "../groups";
+import type { AppProps, AppState } from "../types";
+import type { ExcalidrawElement } from "./types";
+
+export const defaultGetElementLinkFromSelection: Exclude<
+  AppProps["generateLinkForSelection"],
+  undefined
+> = (id, type) => {
+  const url = window.location.href;
+
+  try {
+    const link = new URL(url);
+    link.searchParams.set(ELEMENT_LINK_KEY, id);
+
+    return normalizeLink(link.toString());
+  } catch (error) {
+    console.error(error);
+  }
+
+  return normalizeLink(url);
+};
+
+export const getLinkIdAndTypeFromSelection = (
+  selectedElements: ExcalidrawElement[],
+  appState: AppState,
+): {
+  id: string;
+  type: "element" | "group";
+} | null => {
+  if (
+    selectedElements.length > 0 &&
+    canCreateLinkFromElements(selectedElements)
+  ) {
+    if (selectedElements.length === 1) {
+      return {
+        id: selectedElements[0].id,
+        type: "element",
+      };
+    }
+
+    if (selectedElements.length > 1) {
+      const selectedGroupId = Object.keys(appState.selectedGroupIds)[0];
+
+      if (selectedGroupId) {
+        return {
+          id: selectedGroupId,
+          type: "group",
+        };
+      }
+      return {
+        id: selectedElements[0].groupIds[0],
+        type: "group",
+      };
+    }
+  }
+
+  return null;
+};
+
+export const canCreateLinkFromElements = (
+  selectedElements: ExcalidrawElement[],
+) => {
+  if (selectedElements.length === 1) {
+    return true;
+  }
+
+  if (selectedElements.length > 1 && elementsAreInSameGroup(selectedElements)) {
+    return true;
+  }
+
+  return false;
+};
+
+export const isElementLink = (url: string) => {
+  try {
+    const _url = new URL(url);
+    return (
+      _url.searchParams.has(ELEMENT_LINK_KEY) &&
+      _url.host === window.location.host
+    );
+  } catch (error) {
+    return false;
+  }
+};
+
+export const parseElementLinkFromURL = (url: string) => {
+  try {
+    const { searchParams } = new URL(url);
+    if (searchParams.has(ELEMENT_LINK_KEY)) {
+      const id = searchParams.get(ELEMENT_LINK_KEY);
+      return id;
+    }
+  } catch {}
+
+  return null;
+};