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node_modules/@weborigami/origami/src/dev/changes.js

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+import { trailingSlash, Tree } from "@weborigami/async-tree";
+
+/**
+ * Given an old tree and a new tree, return a tree of changes indicated
+ * by the values: "added", "changed", or "deleted".
+ *
+ * @typedef {import("@weborigami/async-tree").Treelike} Treelike
+ *
+ * @this {import("@weborigami/types").AsyncTree|null}
+ * @param {Treelike} oldTreelike
+ * @param {Treelike} newTreelike
+ */
+export default async function changes(oldTreelike, newTreelike) {
+  const oldTree = Tree.from(oldTreelike, { deep: true, parent: this });
+  const newTree = Tree.from(newTreelike, { deep: true, parent: this });
+
+  const oldKeys = Array.from(await oldTree.keys());
+  const newKeys = Array.from(await newTree.keys());
+
+  const oldKeysNormalized = oldKeys.map(trailingSlash.remove);
+  const newKeysNormalized = newKeys.map(trailingSlash.remove);
+
+  let result;
+
+  for (const oldKey of oldKeys) {
+    const oldNormalized = trailingSlash.remove(oldKey);
+    if (!newKeysNormalized.includes(oldNormalized)) {
+      result ??= {};
+      result[oldKey] = "deleted";
+      continue;
+    }
+
+    const oldValue = await oldTree.get(oldKey);
+    const newValue = await newTree.get(oldKey);
+
+    if (Tree.isAsyncTree(oldValue) && Tree.isAsyncTree(newValue)) {
+      const treeChanges = await changes.call(this, oldValue, newValue);
+      if (treeChanges && Object.keys(treeChanges).length > 0) {
+        result ??= {};
+        result[oldKey] = treeChanges;
+      }
+    } else if (oldValue?.toString && newValue?.toString) {
+      const oldText = oldValue.toString();
+      const newText = newValue.toString();
+      if (oldText !== newText) {
+        result ??= {};
+        result[oldKey] = "changed";
+      }
+    } else {
+      result ??= {};
+      result[oldKey] = "changed";
+    }
+  }
+
+  for (const newKey of newKeys) {
+    const newNormalized = trailingSlash.remove(newKey);
+    if (!oldKeysNormalized.includes(newNormalized)) {
+      result ??= {};
+      result[newKey] = "added";
+    }
+  }
+
+  return result;
+}