fix: handled anchors and added tests for regex (#179)

Author: sukarangolani

src/samplers/string-regex.js

@@ -186,7 +186,9 @@ export function regexSample(pattern) {
     pattern = pattern.toString();
     pattern = pattern.match(/\/(.+?)\//)?.[1] ?? ''; // Remove frontslash from front and back of RegExp
   }
-
+  
+  pattern = pattern.replace(/^(\^)?(.*?)(\$)?$/, '$2'); // Remove anchors if present
+  
   let min
   let max
   let repetitions

test/unit/string.spec.js

@@ -123,7 +123,7 @@ describe('sampleString', () => {
   });
 
   it('should generate valid text for basic regexes', () => {
-    [/#{3}test[1-5]/, /[500-15000]/, /#{2,9}/, /#{5}/, /0x[0-9a-f]{40}/]
+    [/#{3}test[1-5]/, /[500-15000]/, /#{2,9}/, /#{5}/, /0x[0-9a-f]{40}/, /^[0-9]$/]
       .forEach((regexp) => {
         res = sampleString(
           {pattern: regexp.source},