added unique constraint assertion tools

pkg/index.ts

@@ -0,0 +1,10 @@
+export * from "./async";
+export * from "./csv";
+export * from "./dom";
+export * from "./logger";
+export * from "./obj";
+export * from "./queue";
+export * from "./time";
+export * from "./types";
+export * from "./unique";
+export * from "./validators";