no-catch-shadow

禁止 catch 子句参数来自外部作用域的阴影变量

在 IE 8 和更早版本中，如果该变量与 catch 子句参数同名，则 catch 子句参数可以覆盖外部范围内的变量的值。

¥In IE 8 and earlier, the catch clause parameter can overwrite the value of a variable in the outer scope, if that variable has the same name as the catch clause parameter.

var err = "x";

try {
    throw "problem";
} catch (err) {

}

console.log(err)    // err is 'problem', not 'x'
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规则详情

¥Rule Details

此规则旨在防止程序中的意外行为，这些行为可能由 IE 8 及更早版本中的错误引起，其中 catch 子句参数可能会泄漏到外部范围。每当遇到与外部作用域中的变量同名的 catch 子句参数时，此规则都会触发警告。

¥This rule is aimed at preventing unexpected behavior in your program that may arise from a bug in IE 8 and earlier, in which the catch clause parameter can leak into outer scopes. This rule will warn whenever it encounters a catch clause parameter that has the same name as a variable in an outer scope.

此规则的错误代码示例：

¥Examples of incorrect code for this rule:

/*eslint no-catch-shadow: "error"*/

var err = "x";

try {
    throw "problem";
} catch (err) {

}

function error() {
    // ...
};

try {
    throw "problem";
} catch (error) {

}
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此规则的正确代码示例：

¥Examples of correct code for this rule:

/*eslint no-catch-shadow: "error"*/

var err = "x";

try {
    throw "problem";
} catch (e) {

}

function error() {
    // ...
};

try {
    throw "problem";
} catch (e) {

}
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何时不使用

¥When Not To Use It

如果你不需要支持 IE 8 及更早版本，则应关闭此规则。

¥If you do not need to support IE 8 and earlier, you should turn this rule off.

版本

此规则是在 ESLint v0.0.9 中引入。

资源

• 规则源码
• 测试源码