refactor: separate elements logic into a standalone package (#9285)

packages/element/src/index.ts

@@ -0,0 +1,73 @@
+import { isInvisiblySmallElement } from "./sizeHelpers";
+import { isLinearElementType } from "./typeChecks";
+
+import type {
+  ExcalidrawElement,
+  NonDeletedExcalidrawElement,
+  NonDeleted,
+} from "./types";
+
+/**
+ * @deprecated unsafe, use hashElementsVersion instead
+ */
+export const getSceneVersion = (elements: readonly ExcalidrawElement[]) =>
+  elements.reduce((acc, el) => acc + el.version, 0);
+
+/**
+ * Hashes elements' versionNonce (using djb2 algo). Order of elements matters.
+ */
+export const hashElementsVersion = (
+  elements: readonly ExcalidrawElement[],
+): number => {
+  let hash = 5381;
+  for (let i = 0; i < elements.length; i++) {
+    hash = (hash << 5) + hash + elements[i].versionNonce;
+  }
+  return hash >>> 0; // Ensure unsigned 32-bit integer
+};
+
+// string hash function (using djb2). Not cryptographically secure, use only
+// for versioning and such.
+export const hashString = (s: string): number => {
+  let hash: number = 5381;
+  for (let i = 0; i < s.length; i++) {
+    const char: number = s.charCodeAt(i);
+    hash = (hash << 5) + hash + char;
+  }
+  return hash >>> 0; // Ensure unsigned 32-bit integer
+};
+
+export const getVisibleElements = (elements: readonly ExcalidrawElement[]) =>
+  elements.filter(
+    (el) => !el.isDeleted && !isInvisiblySmallElement(el),
+  ) as readonly NonDeletedExcalidrawElement[];
+
+export const getNonDeletedElements = <T extends ExcalidrawElement>(
+  elements: readonly T[],
+) =>
+  elements.filter((element) => !element.isDeleted) as readonly NonDeleted<T>[];
+
+export const isNonDeletedElement = <T extends ExcalidrawElement>(
+  element: T,
+): element is NonDeleted<T> => !element.isDeleted;
+
+const _clearElements = (
+  elements: readonly ExcalidrawElement[],
+): ExcalidrawElement[] =>
+  getNonDeletedElements(elements).map((element) =>
+    isLinearElementType(element.type)
+      ? { ...element, lastCommittedPoint: null }
+      : element,
+  );
+
+export const clearElementsForDatabase = (
+  elements: readonly ExcalidrawElement[],
+) => _clearElements(elements);
+
+export const clearElementsForExport = (
+  elements: readonly ExcalidrawElement[],
+) => _clearElements(elements);
+
+export const clearElementsForLocalStorage = (
+  elements: readonly ExcalidrawElement[],
+) => _clearElements(elements);