chore: improve code cov

Author: mdjastrzebski

src/__tests__/compiler.test.tsx

@@ -28,3 +28,10 @@ test('regex constructor', () => {
   expect(buildRegex('a').test('a')).toBeTruthy();
   expect(buildRegex('a').test('b')).toBeFalsy();
 });
+
+test('buildRegex throws error on unknown element', () => {
+  expect(() =>
+    // @ts-expect-error intentionally passing incorrect object
+    buildRegex({ type: 'unknown' })
+  ).toThrowErrorMatchingInlineSnapshot(`"Unknown elements type unknown"`);
+});

src/compiler.ts

@@ -38,13 +38,13 @@ function compileSingle(element: RegexElement): string {
     return compileCharacterClass(element);
   }
 
-  const compiledChildren = compileList(element.children);
-
   if (element.type === 'repeat') {
+    const compiledChildren = compileList(element.children);
     return compileRepeat(element.config, compiledChildren);
   }
 
   if (isBaseQuantifier(element)) {
+    const compiledChildren = compileList(element.children);
     const compiler = baseQuantifiers[element.type];
     return compiler(compiledChildren);
   }