feat: add 'deepCopy' util

src/utils/deepCopy.ts

@@ -0,0 +1,42 @@
+import type { Primitive } from "type-fest";
+
+/**
+ * This function creates a same-type deep copy of the input without using methods
+ * like `JSON.parse(JSON.stringify(input))` which can't handle certain types of
+ * data like `undefined`, `null`, `Date`, `Map`s, etc.
+ *
+ * > Note: The `structuredClone` Web API method is a better alternative to this
+ *   implementation, but as of May 2023, it's only supported in the very latest
+ *   versions of some browsers like Chrome and Safari, _and_ the Nodejs version
+ *   used in the dev-env would have to be bumped to at least v17 as well. Until
+ *   these compatibility issues are resolved, use this function instead.
+ */
+export const deepCopy = <T extends DeepCopyInput>(input: T): T => {
+  return typeof input === "bigint" ||
+    typeof input === "boolean" ||
+    typeof input === "number" ||
+    typeof input === "string" ||
+    typeof input === "symbol" ||
+    typeof input === "undefined" ||
+    input === null
+    ? input // else typeof input is "object"
+    : input instanceof Date
+    ? (new Date(input.getTime()) as T)
+    : input instanceof Map
+    ? (new Map(Array.from(input).map(([key, value]) => [deepCopy(key), deepCopy(value)])) as T)
+    : input instanceof Set
+    ? (new Set(Array.from(input).map((item) => deepCopy(item))) as T)
+    : Array.isArray(input)
+    ? (input.map((item) => deepCopy(item)) as T)
+    : (Object.fromEntries(
+        Object.entries(input).map(([key, value]) => [key, deepCopy(value)])
+      ) as T);
+};
+
+export type DeepCopyInput =
+  | Primitive
+  | Date
+  | Map<DeepCopyInput, DeepCopyInput>
+  | Set<DeepCopyInput>
+  | Array<DeepCopyInput>
+  | Record<PropertyKey, any>;