one-var-declaration-per-line

要求或禁止在变量声明周围换行

一些开发者在同一行声明多个 var 语句：

🌐 Some developers declare multiple var statements on the same line:

var foo, bar, baz;
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其他人更喜欢每行声明一个 var。

🌐 Others prefer to declare one var per line.

var foo,
    bar,
    baz;
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在项目的代码库中保持其中一种风格有助于保持代码的一致性。

🌐 Keeping to one of these styles across a project’s codebase can help with maintaining code consistency.

规则详情

🌐 Rule Details

此规则强制在变量声明周围使用一致的换行符。此规则会忽略 for 循环条件内的变量声明。

🌐 This rule enforces a consistent newlines around variable declarations. This rule ignores variable declarations inside for loop conditionals.

选项

🌐 Options

此规则有一个字符串选项：

🌐 This rule has a single string option:

• "initializations"（默认）在变量初始化周围强制换行
• "always" 在变量声明周围强制换行

initializations

使用默认 "initializations" 选项时，该规则的错误代码示例：

🌐 Examples of incorrect code for this rule with the default "initializations" option:

/*eslint one-var-declaration-per-line: ["error", "initializations"]*/

var a, b, c = 0;

let d,
    e = 0, f;
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使用默认 "initializations" 选项时，该规则的正确代码示例：

🌐 Examples of correct code for this rule with the default "initializations" option:

/*eslint one-var-declaration-per-line: ["error", "initializations"]*/

var a, b;

let c,
    d;

let e,
    f = 0;
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always

使用 "always" 选项时违反此规则的错误代码示例：

🌐 Examples of incorrect code for this rule with the "always" option:

/*eslint one-var-declaration-per-line: ["error", "always"]*/

var a, b;

let c, d = 0;

const e = 0, f = 0;
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使用 "always" 选项时，此规则的正确代码示例：

🌐 Examples of correct code for this rule with the "always" option:

/*eslint one-var-declaration-per-line: ["error", "always"]*/

var a,
    b;

let c,
    d = 0;
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相关规则

• one-var

版本

此规则是在 ESLint v2.0.0-beta.3 中引入。

资源

• 规则源码
• 测试源码