add js数组访问元素过程文章

Author: igyfhc

.apps/blog/docs/.vitepress/config.mjs

@@ -22,6 +22,7 @@ export default defineConfig({
             {
                 text: '示例',
                 items: [
+                    {text: 'js数组访问元素过程', link: '/array-get-element-process'},
                     {text: 'Markdown 示例', link: '/markdown-examples'},
                     {text: '运行时 API 示例', link: '/api-examples'},
                     {text: '学习使用Github actions', link: '/learn-github-actions'},

.apps/blog/docs/array-get-element-process.md

@@ -0,0 +1,22 @@
+js 数组通过下标访问元素时，会调用下标数字的`toString()`方法。通过以下代码可测试：
+
+```js
+const a = [1, 2, 3, 4, 5];
+
+const index = new class extends Number {
+    toString(radix)
+    {
+        const value = super.toString(radix);
+        console.log(`调用了 toString 转换下标; super.toString(radix): ${value}; radix: ${radix}`);
+        return value;
+    }
+} (2);
+
+console.log(a[index]);
+```
+
+输出：
+```
+调用了 toString 转换下标; super.toString(radix): 2; radix: undefined
+3
+```