Disallow modifying variables that are declared using const (no-const-assign)

不允许改变用const声明的变量 (no-const-assign)

The "extends": "eslint:recommended" property in a configuration file enables this rule.

配置文件中的 "extends": "eslint:recommended" 属性启用了此规则。

We cannot modify variables that are declared using const keyword. It will raise a runtime error.

我们不能修改使用const关键字声明的变量。 它会引发一个运行时错误。

Under non ES2015 environment, it might be ignored merely.

非 ES2015 环境下，它只是可能被忽略。

Rule Details

This rule is aimed to flag modifying variables that are declared using const keyword.

该规则旨在标记修改用const关键字声明的变量。

Examples of incorrect code for this rule:

错误 代码示例：

/*eslint no-const-assign: "error"*/
/*eslint-env es6*/

const a = 0;
a = 1;

/*eslint no-const-assign: "error"*/
/*eslint-env es6*/

const a = 0;
a += 1;

/*eslint no-const-assign: "error"*/
/*eslint-env es6*/

const a = 0;
++a;

Examples of correct code for this rule:

正确 代码示例：

/*eslint no-const-assign: "error"*/
/*eslint-env es6*/

const a = 0;
console.log(a);

/*eslint no-const-assign: "error"*/
/*eslint-env es6*/

for (const a in [1, 2, 3]) { // `a` is re-defined (not modified) on each loop step.
    console.log(a);
}

/*eslint no-const-assign: "error"*/
/*eslint-env es6*/

for (const a of [1, 2, 3]) { // `a` is re-defined (not modified) on each loop step.
    console.log(a);
}

When Not To Use It

If you don’t want to be notified about modifying variables that are declared using const keyword, you can safely disable this rule.

如果你不想收到有关修改用const关键字声明的变量的通知，你可以禁用此规则。

Version

This rule was introduced in ESLint 1.0.0-rc-1.

该规则在 ESLint 1.0.0-rc-1 中被引入。

Resources

• Rule source
• Documentation source