utils-snake-casing: Initial snakeCase utility

* Add initial utility method for snake casing strings

src/snakeCase.ts

@@ -0,0 +1,8 @@
+const snakeCase: (val: string) => string = (val: string): string =>
+  val
+    .trim()
+    .toLowerCase()
+    .replace(/[^a-zA-Z0-9\p{L}]+/gu, '_')
+    .replace(/(\s_)/g, (match, p1) => p1.trimStart());
+
+export default snakeCase;

test/snakeCase.test.ts

@@ -0,0 +1,22 @@
+import snakeCase from '../src/snakeCase';
+
+test.each([
+  [ 'abc def', 'abc_def'],
+  [ 'abc-def', 'abc_def'],
+  [ 'abc_def', 'abc_def'],
+  [ 'abc!def', 'abc_def'],
+  [ 'abc@def', 'abc_def'],
+  [ 'abc%def', 'abc_def'],
+  [ 'abc^def', 'abc_def'],
+  [ 'abc&def', 'abc_def'],
+  [ 'abc*def', 'abc_def'],
+  [ 'abc(def', 'abc_def'],
+  [ 'abc)def', 'abc_def'],
+  [ 'a品cd!e f', 'a品cd_e_f'],
+  [ 'ն !w**sss', 'ն_w_sss'],
+  [ '0 a s w', '0_a_s_w'],
+  [ '0 a 1    w', '0_a_1_w'],
+  [ '0 a     1    w', '0_a_1_w']
+])('it maps the %s object keys entities', (val, expectedVal) => {
+  expect(snakeCase(val)).toBe(expectedVal);
+});