> For the complete documentation index, see [llms.txt](https://mm.ricky.moe/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mm.ricky.moe/javascript/es6-1/const-zhi-shi-dian.md).

# Const知识点

const实际上保证的，并不是变量的值不得改动，而是变量指向的那个内存地址所保存的数据不得改动。

如果真的想将对象冻结，应该使用Object.freeze方法。

```javascript
const foo = Object.freeze({});

// 常规模式时，下面一行不起作用；
// 严格模式时，该行会报错
foo.prop = 123;
```

除了将对象本身冻结，对象的属性也应该冻结。下面是一个将对象彻底冻结的函数。

```javascript
var constantize = (obj) => {
  Object.freeze(obj);
  Object.keys(obj).forEach( (key, i) => {
    if ( typeof obj[key] === 'object' ) {
      constantize( obj[key] );
    }
  });
};
```


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