require calls to isNaN() when checking for NaN (use-isnan)

要求调用 isNaN()检查 NaN (use-isnan)

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。

In JavaScript, NaN is a special value of the Number type. It’s used to represent any of the “not-a-number” values represented by the double-precision 64-bit format as specified by the IEEE Standard for Binary Floating-Point Arithmetic.

在 JavaScript 中，NaN 是 Number 类型的一个特殊值。它被用来表示非数值，这里的数值是指在 IEEE 浮点数算术标准中定义的双精度64位格式的值。

Because NaN is unique in JavaScript by not being equal to anything, including itself, the results of comparisons to NaN are confusing:

因为在 JavaScript 中 NaN 独特之处在于它不等于任何值，包括它本身，与 NaN 进行比较的结果是令人困惑：

• NaN === NaN or NaN == NaN evaluate to false
• NaN !== NaN or NaN != NaN evaluate to true

Therefore, use Number.isNaN() or global isNaN() functions to test whether a value is NaN.

因此，使用 Number.isNaN() 或 全局的 isNaN() 函数来测试一个值是否是 NaN。

Rule Details

This rule disallows comparisons to ‘NaN’.

该规则禁止与 ‘NaN’ 的比较。

Examples of incorrect code for this rule:

错误 代码示例：

/*eslint use-isnan: "error"*/

if (foo == NaN) {
    // ...
}

if (foo != NaN) {
    // ...
}

Examples of correct code for this rule:

正确 代码示例：

/*eslint use-isnan: "error"*/

if (isNaN(foo)) {
    // ...
}

if (!isNaN(foo)) {
    // ...
}

Version

This rule was introduced in ESLint 0.0.6.

该规则在 ESLint 0.0.6 中被引入。

Resources

• Rule source
• Documentation source