Initial

validators/string.ts

@@ -0,0 +1,13 @@
+import { Validator, Args } from "../mod.ts";
+
+export const isString: Validator = {
+  type: "isString",
+  check: (value: any) => {
+    if (typeof value !== 'string' && !(value instanceof String)) {
+      return {};
+    }
+  },
+  message: (value: any, args?: Args) => {
+    return `The value '${value && value.toString()}' has to be a string.`
+  }
+}