add more tests and refactor functions

__tests__/qselect.test.js

@@ -28,11 +28,16 @@ describe('qselect', () => {
       expect(node.innerHTML).toBe('t');
     });
 
-    it('should get a null if selector exists and the context does not exist', () => {
+    it('should get an undefined if selector exists and the context does not exist', () => {
       const node = $('span', 'input');
       expect(node).toBeUndefined();
     });
 
+    it('should get a null if selector does not exist and the context exists', () => {
+      const node = $('input', 'span');
+      expect(node).toBeNull();
+    });
+
     it('should be a dom element if selector exists', () => {
       const node = $('div');
       expect(isDom(node)).toBeTruthy();
@@ -48,6 +53,12 @@ describe('qselect', () => {
       expect(isDom(node)).toBeFalsy();
     });
 
+    it('should throw if selector is not a dom string and context exists', () => {
+      expect(() => {
+        $(true, 'span');
+      }).toThrowError(errorSelector);
+    });
+
     it('should throw if selector is Nan', () => {
       expect(() => {
         $(NaN);
@@ -148,6 +159,17 @@ describe('qselect', () => {
       expect(node.length).toBeGreaterThanOrEqual(1);
     });
 
+    it('should be undefined if selector is not a dom string and context exists', () => {
+      const node = $$(true, 'span');
+      expect(node).toBeUndefined();
+    });
+
+    it('should throw if selector exists and context is not a dom string', () => {
+      expect(() => {
+        $$('span', true);
+      }).toThrowError(errorSelector);
+    });
+
     it('should throw if selector is Nan', () => {
       expect(() => {
         $$(NaN);

index.js

@@ -9,12 +9,12 @@ const isSelectorString = (selector) => {
   throw new Error('Selector must be a string');
 };
 
-const $ = (selector, context = undefined) => {
-  if (context) {
-    const root = document.querySelector(context);
+const $ = (selector, rootNode = undefined) => {
+  if (rootNode) {
+    const root = document.querySelector(rootNode);
 
-    if (isDom(root)) {
-      return isSelectorString(selector) ? root.querySelector(selector) : undefined;
+    if (isDom(root) && isSelectorString(selector)) {
+      return root.querySelector(selector);
     }
   } else if (isSelectorString(selector)) {
     return document.querySelector(selector);
@@ -23,12 +23,12 @@ const $ = (selector, context = undefined) => {
   return undefined;
 };
 
-const $$ = (selector, context = undefined) => {
-  if (context) {
+const $$ = (selector, rootNode = undefined) => {
+  if (rootNode) {
     const root = document.querySelector(selector);
 
-    if (isDom(root)) {
-      return [...root.querySelectorAll(context)];
+    if (isDom(root) && isSelectorString(rootNode)) {
+      return [...root.querySelectorAll(rootNode)];
     }
   } else if (isSelectorString(selector)) {
     return [...document.querySelectorAll(selector)];