feat(writekit): rename @robonen/editor to @robonen/writekit

Rename the rich-text editor package and all Editor* exports to Writekit*;
remove the old vue/editor tree.

vue/writekit/src/model/attrs.ts

@@ -0,0 +1,57 @@
+/**
+ * Attribute values are JSON-serializable so documents round-trip losslessly and
+ * a CRDT adapter can map them onto its own primitives without special-casing.
+ */
+export type AttrValue
+  = | string
+    | number
+    | boolean
+    | null
+    | readonly AttrValue[]
+    | { readonly [key: string]: AttrValue };
+
+export type Attrs = Readonly<Record<string, AttrValue>>;
+
+/**
+ * Structural equality for two attribute values. Order-insensitive for object
+ * keys, deep for arrays/objects. Used by mark/attr deduplication and tests.
+ */
+export function attrValueEq(a: AttrValue | undefined, b: AttrValue | undefined): boolean {
+  if (a === b)
+    return true;
+
+  if (a === null || b === null || a === undefined || b === undefined)
+    return a === b;
+
+  const aArr = Array.isArray(a);
+  const bArr = Array.isArray(b);
+
+  if (aArr || bArr) {
+    if (!aArr || !bArr || a.length !== b.length)
+      return false;
+
+    return a.every((v, i) => attrValueEq(v, b[i]));
+  }
+
+  if (typeof a === 'object' && typeof b === 'object')
+    return attrsEq(a as Attrs, b as Attrs);
+
+  return false;
+}
+
+/**
+ * Structural equality for attribute bags. `undefined` and `{}` are equivalent
+ * so `{ type: 'bold' }` equals `{ type: 'bold', attrs: {} }`.
+ */
+export function attrsEq(a?: Attrs, b?: Attrs): boolean {
+  if (a === b)
+    return true;
+
+  const aKeys = a ? Object.keys(a) : [];
+  const bKeys = b ? Object.keys(b) : [];
+
+  if (aKeys.length !== bKeys.length)
+    return false;
+
+  return aKeys.every(key => attrValueEq(a![key], b?.[key]));
+}