Initial commit

node_modules/fast-equals/recipes/using-meta-in-comparison.md

@@ -0,0 +1,20 @@
+# Using `meta` in comparison
+
+Sometimes a "pure" equality between two objects is insufficient, because the comparison relies on some external state. While these kinds of scenarios should generally be avoided, it is possible to handle them with a custom internal comparator that checks `meta` values.
+
+```ts
+import { createCustomEqual } from 'fast-equals';
+
+interface Meta {
+  value: string;
+}
+
+const meta: Meta = { value: 'baz' };
+
+const deepEqual = createCustomEqual<Meta>({
+  createInternalComparator:
+    (compare) => (a, b, _keyA, _keyB, _parentA, _parentB, state) =>
+      compare(a, b, state) || a === state.meta.value || b === state.meta.value,
+  createState: () => ({ meta }),
+});
+```