Index

max-len

强制执行最大行长度

Important

This rule was deprecated in ESLint v8.53.0. It will be removed in v11.0.0. Please use the corresponding rule in @stylistic/eslint-plugin.

Learn more

任何语言中非常长的代码行都可能难以阅读。为了提高可读性和可维护性，许多程序员已经制定了一种规范，将代码行限制在X个字符以内（传统上是80个字符）。

🌐 Very long lines of code in any language can be difficult to read. In order to aid in readability and maintainability many coders have developed a convention to limit lines of code to X number of characters (traditionally 80 characters).

var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" }; // very long

规则详情

🌐 Rule Details

此规则强制执行最大行长度，以提高代码的可读性和可维护性。行的长度定义为行中的 Unicode 字符数。

🌐 This rule enforces a maximum line length to increase code readability and maintainability. The length of a line is defined as the number of Unicode characters in the line.

选项

🌐 Options

此规则最多可以有两个数字作为位置参数（用于 code 和 tabWidth 选项），然后是一个对象选项（提供的位置参数具有优先权）：

🌐 This rule can have up to two numbers as positional arguments (for code and tabWidth options), followed by an object option (provided positional arguments have priority):

  • "code"（默认 80）强制执行最大行长度
  • "tabWidth"（默认值 4）指定制表符的字符宽度
  • "comments" 对评论的最大行长度进行强制限制；默认值为 code
  • "ignorePattern" 忽略与正则表达式匹配的行；只能匹配单行，在 YAML 或 JSON 中书写时需要双重转义
  • "ignoreComments": true 会忽略所有尾随注释以及单独一行的注释
  • "ignoreTrailingComments": true 仅忽略行尾注释
  • "ignoreUrls": true 会忽略包含 URL 的行
  • "ignoreStrings": true 忽略包含双引号或单引号字符串的行
  • "ignoreTemplateLiterals": true 忽略包含模板字符串的行
  • "ignoreRegExpLiterals": true 忽略包含正则表达式字面量的行

code

使用默认 { "code": 80 } 选项时，该规则的错误代码示例：

🌐 Examples of incorrect code for this rule with the default { "code": 80 } option:

在线运行 
/*eslint max-len: ["error", { "code": 80 }]*/

var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };

使用默认 { "code": 80 } 选项时，该规则的正确代码示例：

🌐 Examples of correct code for this rule with the default { "code": 80 } option:

在线运行 
/*eslint max-len: ["error", { "code": 80 }]*/

var foo = {
  "bar": "This is a bar.",
  "baz": { "qux": "This is a qux" },
  "easier": "to read"
};

tabWidth

使用默认 { "tabWidth": 4 } 选项时，该规则的错误代码示例：

🌐 Examples of incorrect code for this rule with the default { "tabWidth": 4 } option:

::: 错误

/*eslint max-len: ["error", { "code": 80, "tabWidth": 4 }]*/

		var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };

:::

使用默认 { "tabWidth": 4 } 选项时，该规则的正确代码示例：

🌐 Examples of correct code for this rule with the default { "tabWidth": 4 } option:

::: 正确

/*eslint max-len: ["error", { "code": 80, "tabWidth": 4 }]*/

		var foo = {
				"bar": "This is a bar.",
				"baz": { "qux": "This is a qux" }
		};

:::

comments

使用 { "comments": 65 } 选项时违反此规则的错误代码示例：

🌐 Examples of incorrect code for this rule with the { "comments": 65 } option:

在线运行 
/*eslint max-len: ["error", { "comments": 65 }]*/

/**
 * This is a comment that violates the maximum line length we have specified
**/

ignoreComments

使用 { "ignoreComments": true } 选项时，此规则的正确代码示例：

🌐 Examples of correct code for this rule with the { "ignoreComments": true } option:

在线运行 
/*eslint max-len: ["error", { "ignoreComments": true }]*/

/**
 * This is a really really really really really really really really really long comment
**/

ignoreTrailingComments

使用 { "ignoreTrailingComments": true } 选项时，此规则的正确代码示例：

🌐 Examples of correct code for this rule with the { "ignoreTrailingComments": true } option:

在线运行 
/*eslint max-len: ["error", { "ignoreTrailingComments": true }]*/

var foo = 'bar'; // This is a really really really really really really really long comment

ignoreUrls

使用 { "ignoreUrls": true } 选项时，此规则的正确代码示例：

🌐 Examples of correct code for this rule with the { "ignoreUrls": true } option:

在线运行 
/*eslint max-len: ["error", { "ignoreUrls": true }]*/

var url = 'https://www.example.com/really/really/really/really/really/really/really/long';

ignoreStrings

使用 { "ignoreStrings": true } 选项时，此规则的正确代码示例：

🌐 Examples of correct code for this rule with the { "ignoreStrings": true } option:

在线运行 
/*eslint max-len: ["error", { "ignoreStrings": true }]*/

var longString = 'this is a really really really really really long string!';

ignoreTemplateLiterals

使用 { "ignoreTemplateLiterals": true } 选项时，此规则的正确代码示例：

🌐 Examples of correct code for this rule with the { "ignoreTemplateLiterals": true } option:

在线运行 
/*eslint max-len: ["error", { "ignoreTemplateLiterals": true }]*/

var longTemplateLiteral = `this is a really really really really really long template literal!`;

ignoreRegExpLiterals

使用 { "ignoreRegExpLiterals": true } 选项时，此规则的正确代码示例：

🌐 Examples of correct code for this rule with the { "ignoreRegExpLiterals": true } option:

在线运行 
/*eslint max-len: ["error", { "ignoreRegExpLiterals": true }]*/

var longRegExpLiteral = /this is a really really really really really long regular expression!/;

ignorePattern

使用 ignorePattern 选项时，此规则的正确代码示例：

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

在线运行 
/*eslint max-len:
["error", { "ignorePattern": "^\\s*var\\s.+=\\s*require\\s*\\(" }]*/

var dep = require('really/really/really/really/really/really/really/really/long/module');

版本

此规则是在 ESLint v0.0.9 中引入。

资源