max-len

强制执行最大行长度

此规则在 ESLint v8.53.0 中已弃用。请在 @stylistic/eslint-plugin-js 中使用 相应的规则。

¥This rule was deprecated in ESLint v8.53.0. Please use the corresponding rule in @stylistic/eslint-plugin-js.

任何语言的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，许多编码人员制定了一种约定，将代码行限制为 X 个字符（传统上为 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
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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 Unicode 字符的数量。

¥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（对于 code 和 tabWidth 选项），后跟一个对象选项（前提是位置参数具有优先级）：

¥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）强制最大行长度

  ¥"code" (default 80) enforces a maximum line length

• "tabWidth"（默认 4）指定制表符的字符宽度

  ¥"tabWidth" (default 4) specifies the character width for tab characters

• "comments" 强制注释的最大行长度；默认值为 code

  ¥"comments" enforces a maximum line length for comments; defaults to value of code

• "ignorePattern" 忽略与正则表达式匹配的行；只能匹配单行，用 YAML 或 JSON 写的时候需要双重转义

  ¥"ignorePattern" ignores lines matching a regular expression; can only match a single line and need to be double escaped when written in YAML or JSON

• "ignoreComments": true 忽略所有尾随注释和自己行上的注释

  ¥"ignoreComments": true ignores all trailing comments and comments on their own line

• "ignoreTrailingComments": true 仅忽略尾随注释

  ¥"ignoreTrailingComments": true ignores only trailing comments

• "ignoreUrls": true 忽略包含 URL 的行

  ¥"ignoreUrls": true ignores lines that contain a URL

• "ignoreStrings": true 忽略包含双引号或单引号字符串的行

  ¥"ignoreStrings": true ignores lines that contain a double-quoted or single-quoted string

• "ignoreTemplateLiterals": true 忽略包含模板字面量的行

  ¥"ignoreTemplateLiterals": true ignores lines that contain a template literal

• "ignoreRegExpLiterals": true 忽略包含 RegExp 字面量的行

  ¥"ignoreRegExpLiterals": true ignores lines that contain a RegExp literal

code

使用默认 { "code": 80 } 选项的此规则的错误代码示例：

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

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

var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" }, "difficult": "to read" };
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使用默认 { "code": 80 } 选项的此规则的正确代码示例：

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

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

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

使用默认 { "tabWidth": 4 } 选项的此规则的错误代码示例：

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

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

		var foo = { "bar": "This is a bar.", "baz": { "qux": "This is a qux" } };
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使用默认 { "tabWidth": 4 } 选项的此规则的正确代码示例：

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

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

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

使用 { "comments": 65 } 选项的此规则的错误代码示例：

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

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

/**

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

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

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

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

/**

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

使用 ignorePattern 选项的此规则的正确代码示例：

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

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

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

• complexity
• max-depth
• max-nested-callbacks
• max-params
• max-statements

版本

此规则是在 ESLint v0.0.9 中引入。

资源

• 规则源码
• 测试源码