disallow reassigning exceptions in catch clauses (no-ex-assign)

禁止对 catch 子句中的异常重新赋值 (no-ex-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。

If a catch clause in a try statement accidentally (or purposely) assigns another value to the exception parameter, it impossible to refer to the error from that point on. Since there is no arguments object to offer alternative access to this data, assignment of the parameter is absolutely destructive.

在 try 语句中的 catch 子句中，如果意外地（或故意地）给异常参数赋值，是不可能引用那个位置的错误的。由于没有 arguments 对象提供额外的方式访问这个异常，对它进行赋值绝对是毁灭性的。

Rule Details

This rule disallows reassigning exceptions in catch clauses.

该规则禁止对 catch 子句中的异常重新赋值。

Examples of incorrect code for this rule:

错误 代码示例：

/*eslint no-ex-assign: "error"*/

try {
    // code
} catch (e) {
    e = 10;
}

Examples of correct code for this rule:

正确 代码示例：

/*eslint no-ex-assign: "error"*/

try {
    // code
} catch (e) {
    var foo = 10;
}

Further Reading

• The “catch” with try…catch by Ben Alman explains how the exception identifier can leak into the outer scope in IE 6-8

Version

This rule was introduced in ESLint 0.0.9.

该规则在 ESLint 0.0.9 中被引入。

Resources

• Rule source
• Documentation source