diff --git a/src/core/validateField.ts b/src/core/validateField.ts
index 00ed4a1..95e1cee 100644
--- a/src/core/validateField.ts
+++ b/src/core/validateField.ts
@@ -16,13 +16,16 @@ export function validateField(
 ): Array<FieldError> {
   const errors: Array<FieldError> = [];
   try {
+
+    if (!_utils.isString(value))
+      throw new TypeError("'value' must be a string");
+
+    if (!_utils.isString(name)) throw new TypeError("'name' must be a string");
+
     const configMap: ConfigMap = {
       minLength: (value: string, criterion: number, message: string) => {
         /*--- Error Guards ---*/
 
-        if (!_utils.isString(value))
-          throw new TypeError("'value' must be a string");
-
         if (!_utils.isNumber(criterion))
           throw new TypeError("'criterion' must be a number");
 
@@ -38,9 +41,6 @@ export function validateField(
       maxLength: (value: string, criterion: number, message: string) => {
         /*--- Error Guards ---*/
 
-        if (!_utils.isString(value))
-          throw new TypeError("'value' must be a string");
-
         if (!_utils.isNumber(criterion))
           throw new TypeError("'criterion' must be a number");
 
@@ -56,9 +56,6 @@ export function validateField(
       pattern: (value: string, criterion: RegExp, message: string) => {
         /*--- Error Guards ---*/
 
-        if (!_utils.isString(value))
-          throw new TypeError("'value' must be a string");
-
         // if (!_utils.isRegExp(criterion))
         //   throw new TypeError("'criterion' must be a RegExp");
 
@@ -72,9 +69,6 @@ export function validateField(
       custom: (value: string, criterion: CustomFunction, message: string) => {
         /*--- Error Guards ---*/
 
-        if (!_utils.isString(value))
-          throw new TypeError("'value' must be a string");
-
         // if (!_utils.isFunction(criterion))
         //   throw new TypeError("'criterion' must be a function");
 
@@ -90,9 +84,6 @@ export function validateField(
       required: (value: string, criterion: boolean, message: string) => {
         /*--- Error Guards ---*/
 
-        if (!_utils.isString(value))
-          throw new TypeError("'value' must be a string");
-
         // if (!_utils.isBoolean(criterion))
         //   throw new TypeError("'criterion' must be a boolean");
 
diff --git a/src/internal/do-keys-match.ts b/src/internal/do-keys-match.ts
index 39d0de4..401ce70 100644
--- a/src/internal/do-keys-match.ts
+++ b/src/internal/do-keys-match.ts
@@ -1,18 +1,19 @@
 import { FormDataShape, NameRuleMap } from "../types";
+import { MappingError } from "./error-management";
 
 export function doKeysMatch(data: FormDataShape, NameRuleMap: NameRuleMap) {
   const dataKeys = Object.keys(data);
   const NameRuleMapKeys = Object.keys(NameRuleMap);
 
   if (dataKeys.length !== NameRuleMapKeys.length) {
-    throw new Error(
+    throw new MappingError(
       `Data keys and NameRuleMap keys do not match. Data keys: ${dataKeys}, NameRuleMap keys: ${NameRuleMapKeys}`
     );
   }
 
   dataKeys.forEach((key) => {
     if (!NameRuleMapKeys.includes(key)) {
-      throw new Error(
+      throw new MappingError(
         `Data keys and NameRuleMap keys do not match. Data keys: ${dataKeys}, NameRuleMap keys: ${NameRuleMapKeys}`
       );
     }
diff --git a/src/internal/error-management.ts b/src/internal/error-management.ts
index 39a4011..7ad91c2 100644
--- a/src/internal/error-management.ts
+++ b/src/internal/error-management.ts
@@ -2,7 +2,7 @@ type ERROR_NAMES = "TYPE_ERROR" | "MAPPING_ERROR";
 
 class MappingError extends Error {
   constructor(
-    message: string = "Validation Error",
+    message: string = "Mapping Error",
     name: ERROR_NAMES = "MAPPING_ERROR"
   ) {
     super();
@@ -28,13 +28,13 @@ class TypeError extends Error {
 function handleError(error: Error): void {
   switch (error.constructor) {
     case TypeError:
-      console.log("Type Error:", error.message);
+      console.error("Type Error:", error.message);
       break;
     case MappingError:
-      console.log("Mapping Error:", error.message);
+      console.error("Mapping Error:", error.message);
       break;
     default:
-      console.log(
+      console.error(
         "Internal Error",
         error.message,
         "Please report this at" +
diff --git a/src/types/index.ts b/src/types/index.ts
index 4cdb3f9..e50cbf9 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -1,33 +1,43 @@
+export interface CustomFunction {
+  (value: string): boolean;
+}
+
+export interface KeyValuePair {
+  [key: string]: string;
+}
+
 export type Criterion = string | number | CustomFunction | boolean | RegExp;
 
-export interface Rule {
-  criterion: Criterion;
+export interface Rule<TCriterion = Criterion> {
+  criterion: TCriterion;
   message: string;
 }
 
-export type FormDataShape = KeyValuePair | { [k: string]: FormDataEntryValue };
+export interface RequiredRule extends Rule<boolean> {}
+
+export interface MinLengthRule extends Rule<number> {}
+
+export interface MaxLengthRule extends Rule<number> {}
+
+export interface PatternRule extends Rule<RegExp> {}
+
+export interface CustomRule extends Rule<CustomFunction> {}
 
 export interface RulesObject {
-  required?: Rule;
-  minLength?: Rule;
-  maxLength?: Rule;
-  pattern?: Rule;
-  custom?: Rule;
+  required?: RequiredRule;
+  minLength?: MinLengthRule;
+  maxLength?: MaxLengthRule;
+  pattern?: PatternRule;
+  custom?: CustomRule;
 }
 
+export type FormDataShape = KeyValuePair | { [k: string]: FormDataEntryValue };
+
 export interface FieldError {
   name: string;
   message: string;
 }
 
-export interface CustomFunction {
-  (value: string): boolean;
-}
-
-export interface KeyValuePair {
-  [key: string]: string;
-}
-
 export interface NameRuleMap {
   [key: string]: RulesObject;
 }