add: unit and integration testing

app/node_modules/@paralleldrive/cuid2/index.d.ts

@@ -0,0 +1,19 @@
+declare namespace cuid2 {
+  export function getConstants(): {
+    defaultLength: number
+    bigLength: number
+  }
+
+  export function init(options?: {
+    random?: () => number
+    counter?: () => number
+    length?: number
+    fingerprint?: string
+  }): () => string
+
+  export function isCuid(id: string): boolean
+
+  export function createId(): string
+}
+
+export = cuid2;