Disallow Shadowing of Variables Inside of catch (no-catch-shadow)

不允许在 catch 语句中遮盖变量 (no-catch-shadow)

This rule was deprecated in ESLint v5.1.0.

该规则在 ESLint v5.1.0 中 已弃用。

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.

在 IE 8 及更早的版本，catch 子句的参数可以覆盖一个外部的同名变量的值。

var err = "x";

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

}

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

Rule Details

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.

在 IE 8 及更早版本中，catch 子句的参数会泄露到外部范围，该规则的目的就是避免这种 bug 导致的意外行为。但 catch 子句中的参数与外部范围的变量同名时，该规则将发出警告。

Examples of incorrect code for this rule:

错误 代码示例：

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

var err = "x";

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

}

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

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

}

Examples of correct code for this rule:

正确 代码示例：

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

var err = "x";

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

}

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

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

}

When Not To Use It

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

如果你并不需要支持 IE 8 及更早的版本，你应该关闭此规则。

Version

This rule was introduced in ESLint 0.0.9.

该规则在 ESLint 0.0.9 中被引入。

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