guard-for-in
要求 for-in 循环包含 if 语句
使用 for in 循环遍历对象时，会包括通过原型链继承的属性。这种行为可能导致你的 for 循环中出现意外的项目。
🌐 Looping over objects with a for in loop will include properties that are inherited through the prototype chain. This behavior can lead to unexpected items in your for loop.
for (key in foo) {
doSomething(key);
}
对于不支持 ES2022 的代码库，可以使用 Object.prototype.hasOwnProperty.call(foo, key) 来检查该属性是否不是继承的。
🌐 For codebases that do not support ES2022, Object.prototype.hasOwnProperty.call(foo, key) can be used as a check that the property is not inherited.
对于支持 ES2022 的代码库，Object.hasOwn(foo, key) 可以作为一个更简短的替代方案；参见 prefer-object-has-own。
🌐 For codebases that do support ES2022, Object.hasOwn(foo, key) can be used as a shorter alternative; see prefer-object-has-own.
请注意，仅检查 foo.hasOwnProperty(key) 在某些情况下可能会导致错误；请参阅 no-prototype-builtins。
🌐 Note that simply checking foo.hasOwnProperty(key) is likely to cause an error in some cases; see no-prototype-builtins.
规则详情
🌐 Rule Details
此规则旨在防止因在循环中使用 for in 循环而不对结果进行过滤而可能产生的意外行为。因此，当 for in 循环未使用 if 语句过滤其结果时，它会发出警告。
🌐 This rule is aimed at preventing unexpected behavior that could arise from using a for in loop without filtering the results in the loop. As such, it will warn when for in loops do not filter their results with an if statement.
此规则的错误代码示例：
🌐 Examples of incorrect code for this rule:
/*eslint guard-for-in: "error"*/
for (key in foo) {
doSomething(key);
}
符合此规则的正确代码示例：
🌐 Examples of correct code for this rule:
/*eslint guard-for-in: "error"*/
for (key in foo) {
if (Object.hasOwn(foo, key)) {
doSomething(key);
}
}
for (key in foo) {
if (Object.prototype.hasOwnProperty.call(foo, key)) {
doSomething(key);
}
}
for (key in foo) {
if ({}.hasOwnProperty.call(foo, key)) {
doSomething(key);
}
}
选项
🌐 Options
此规则没有选项。
🌐 This rule has no options.
相关规则
版本
此规则是在 ESLint v0.0.6 中引入。