feat: throw a TypeError if hash is not a string for murmur functions

The hash functions murmurhash2_x86_32 and murmurhash3_x86_32 now throw a TypeError with a helpful
error message if the value passed for the hash is not a string. Beforhand both functions already
throwed an error, but with a non helpful message.

Author: MartinHelmut

src/fns/murmurhash2_x86_32.js

@@ -1,5 +1,10 @@
 /** @module number-generator/lib/murmurhash2_x86_32 */
-import { uMul32Getter, uInt32Getter, throwInvalidMurmurSeed } from '../utils';
+import {
+    uMul32Getter,
+    uInt32Getter,
+    throwInvalidMurmurSeed,
+    throwInvalidStringHash
+} from '../utils';
 
 /**
  * Generate a non-cryptic number hash with murmur2 algorithm
@@ -31,13 +36,15 @@ export default (() => {
 
     /**
      * Generate a non-cryptic number hash with murmur2 algorithm
-
+     *
+     * @throws {TypeError} Throws an exception if hash is not a string
      * @throws {TypeError} Throws an exception if seed is a float
      * @param {string} hash The base string hash to generate number
      * @param {number} [seed=0] An optional seed value
      * @return {number} Generated number
      */
     function murmurhash2_x86_32(hash, seed = 0) {
+        throwInvalidStringHash(hash, 'murmurhash2_x86_32');
         throwInvalidMurmurSeed(seed);
 
         let currentIndex = 0;

src/fns/murmurhash3_x86_32.js

@@ -1,5 +1,10 @@
 /** @module number-generator/lib/murmurhash3_x86_32 */
-import { uMul32Getter, uInt32Getter, throwInvalidMurmurSeed } from '../utils';
+import {
+    uMul32Getter,
+    uInt32Getter,
+    throwInvalidMurmurSeed,
+    throwInvalidStringHash
+} from '../utils';
 
 /**
  * Generate a non-cryptic number hash with murmur3 algorithm
@@ -33,13 +38,15 @@ export default (() => {
 
     /**
      * Generate a non-cryptic number hash with murmur3 algorithm
-
+     *
+     * @throws {TypeError} Throws an exception if hash is not a string
      * @throws {TypeError} Throws an exception if seed is a float
      * @param {string} hash The base string hash to generate number
      * @param {number} [seed=0] An optional seed value
      * @return {number} Generated number
      */
     function murmurhash3_x86_32(hash, seed = 0) {
+        throwInvalidStringHash(hash, 'murmurhash3_x86_32');
         throwInvalidMurmurSeed(seed);
 
         const remainder = hash.length % 4;

src/utils.js

@@ -57,3 +57,19 @@ export function throwInvalidAleaSeed(seed) {
         );
     }
 }
+
+/**
+ * Throw an error if a given hash is not a string
+ *
+ * @private
+ * @param {string} hash The possible empty hash value
+ * @param {string} [functionName] An optional function to enhance the error message
+ */
+export function throwInvalidStringHash(hash, functionName = '') {
+    if (typeof hash !== 'string') {
+        const errorMessagePrefix = functionName ? `${functionName}() ` : '';
+        throw new TypeError(
+            `${errorMessagePrefix}first argument is not a string.`
+        );
+    }
+}