Require or disallow padding lines between statements (padding-line-between-statements)

要求或禁止在语句间填充空行 (padding-line-between-statements)

The --fix option on the command line can automatically fix some of the problems reported by this rule.

命令行中的 --fix 选项可以自动修复一些该规则报告的问题。

This rule requires or disallows blank lines between the given 2 kinds of statements. Properly blank lines help developers to understand the code.

该规则要求或禁止在给定的两种语句间填充空行。正确的空行可以帮助开发人员理解代码。

For example, the following configuration requires a blank line between a variable declaration and a return statement.

例如，以下配置要求在变量声明和 return 语句之间有一行空行。

/*eslint padding-line-between-statements: [
    "error",
    { blankLine: "always", prev: "var", next: "return" }
]*/

function foo() {
    var a = 1;

    return a;
}

Rule Details

This rule does nothing if no configurations are provided.

如果没有提供配置，则此规则不执行任何操作。

A configuration is an object which has 3 properties; blankLine, prev and next. For example, { blankLine: "always", prev: "var", next: "return" } means “one or more blank lines are required between a variable declaration and a return statement.” You can supply any number of configurations. If a statement pair matches multiple configurations, the last matched configuration will be used.

配置是具有三个属性的对象：：blankLine、prev 和 next。例如，{ blankLine: "always", prev: "var", next: "return" } 表示 “要求在变量声明和 return 语句之间有一行或多行空行空白”。你可以提供任意数量的配置。如果语句对匹配多个配置，则将使用最后匹配的配置。

{
    "padding-line-between-statements": [
        "error",
        { "blankLine": LINEBREAK_TYPE, "prev": STATEMENT_TYPE, "next": STATEMENT_TYPE },
        { "blankLine": LINEBREAK_TYPE, "prev": STATEMENT_TYPE, "next": STATEMENT_TYPE },
        { "blankLine": LINEBREAK_TYPE, "prev": STATEMENT_TYPE, "next": STATEMENT_TYPE },
        { "blankLine": LINEBREAK_TYPE, "prev": STATEMENT_TYPE, "next": STATEMENT_TYPE },
        ...
    ]
}

• LINEBREAK_TYPE is one of the following.
• LINEBREAK_TYPE 是以下一种：
  • "any" just ignores the statement pair.
  • "any" 忽略成对语句。
  • "never" disallows blank lines.
  • "never" 禁止出现空行。
  • "always" requires one or more blank lines. Note it does not count lines that comments exist as blank lines.
  • "always" 要求一行或多行空行。注意它不计算注释中存在的空行。
• STATEMENT_TYPE is one of the following, or an array of the following.
• STATEMENT_TYPE 是以下一个或多个：
  • "*" is wildcard. This matches any statements.
  • "*" 通配符。匹配任何语句。
  • "block" is lonely blocks.
  • "block" 是单个块。
  • "block-like" is block like statements. This matches statements that the last token is the closing brace of blocks; e.g. { }, if (a) { }, and while (a) { }. Also matches immediately invoked function expression statements.
  • "block-like" 像块的语句。匹配语句的最后一个 token 是闭括号的块；如 { }、if (a) { } 和 while (a) { }。也匹配立即调用的函数表达式语句。
  • "break" is break statements.
  • "break" 是 break 语句。
  • "case" is case labels.
  • "case" 是 case 标签。
  • "cjs-export" is export statements of CommonJS; e.g. module.exports = 0, module.exports.foo = 1, and exports.foo = 2. This is a special case of assignment.
  • "cjs-export" 是 CommonJS 的 export 语句；如 module.exports = 0、module.exports.foo = 1 和 exports.foo = 2。这是一种特殊的赋值。
  • "cjs-import" is import statements of CommonJS; e.g. const foo = require("foo"). This is a special case of variable declarations.
  • "cjs-import" 是 CommonJS 的 import 语句; 如 const foo = require("foo")。这是一种特殊的变量声明。
  • "class" is class declarations.
  • "class" 是 class 声明。
  • "const" is const variable declarations, both single-line and multiline.
  • "const" 是 const 变量声明，包括单行和多行。
  • "continue" is continue statements.
  • "continue" 是 continue 语句。
  • "debugger" is debugger statements.
  • "debugger" 是 debugger 语句。
  • "default" is default labels.
  • "default" 是 default 标签。
  • "directive" is directive prologues. This matches directives; e.g. "use strict".
  • "directive" 是指令序言。它匹配指令，如 "use strict"。
  • "do" is do-while statements. This matches all statements that the first token is do keyword.
  • "do" 是 do-while 语句。它匹配所有以 do 关键字开始的语句。
  • "empty" is empty statements.
  • "empty" 是空语句。
  • "export" is export declarations.
  • "export" 是 export 声明。
  • "expression" is expression statements.
  • "expression" 是表达式语句。
  • "for" is for loop families. This matches all statements that the first token is for keyword.
  • "for" 是 for 循环. 它匹配所有以 for 关键字开始的语句。
  • "function" is function declarations.
  • "function" 是函数声明。
  • "if" is if statements.
  • "if" 是 if 语句。
  • "iife" is immediately invoked function expression statements. This matches calls on a function expression, optionally prefixed with a unary operator.
  • "iife" 是立即调用的函数表达式语句。这将匹配对函数表达式的调用，函数表达式可选前缀为一元运算符。
  • "import" is import declarations.
  • "import" 是 import 语句。
  • "let" is let variable declarations, both single-line and multiline.
  • "let" 是 let 变量声明，包括单行和多行。
  • "multiline-block-like" is block like statements. This is the same as block-like type, but only if the block is multiline.
  • "multiline-block-like" 是像块的语句。它和 block-like 类型相同，但只应用于多行块。
  • "multiline-const" is multiline const variable declarations.
  • "multiline-const" 是多行 const 变量声明。
  • "multiline-expression" is expression statements. This is the same as expression type, but only if the statement is multiline.
  • "multiline-expression" 是表达式语句。同 expression 类型一下，但只应用于多行语句。
  • "multiline-let" is multiline let variable declarations.
  • "multiline-let" 是多行 let 变量声明。
  • "multiline-var" is multiline var variable declarations.
  • "multiline-var" 是多行 var 变量声明。
  • "return" is return statements.
  • "return" 是 return 语句。
  • "singleline-const" is single-line const variable declarations.
  • "singleline-const" 是单行 const 变量声明。
  • "singleline-let" is single-line let variable declarations.
  • "singleline-let" 是单行 let 变量声明。
  • "singleline-var" is single-line var variable declarations.
  • "singleline-var" 是单行 var 变量声明。
  • "switch" is switch statements.
  • "switch" 是 switch 语句。
  • "throw" is throw statements.
  • "throw" 是 throw 语句。
  • "try" is try statements.
  • "try" 是 try 语句。
  • "var" is var variable declarations, both single-line and multiline.
  • "var" 是 var 变量声明，包括单行和多行。
  • "while" is while loop statements.
  • "while" 是 while 循环。
  • "with" is with statements.
  • "with" 是 with 语句。

Examples

This configuration would require blank lines before all return statements, like the newline-before-return rule.

该配置会要求所有的 return 语句前都有空行，就像 newline-before-return规则一样。

Examples of incorrect code for the [{ blankLine: "always", prev: "*", next: "return" }] configuration:

配置 [{ blankLine: "always", prev: "*", next: "return" }] 的 错误 代码示例：

/*eslint padding-line-between-statements: [
    "error",
    { blankLine: "always", prev: "*", next: "return" }
]*/

function foo() {
    bar();
    return;
}

Examples of correct code for the [{ blankLine: "always", prev: "*", next: "return" }] configuration:

配置 [{ blankLine: "always", prev: "*", next: "return" }] 的 正确 代码示例：

/*eslint padding-line-between-statements: [
    "error",
    { blankLine: "always", prev: "*", next: "return" }
]*/

function foo() {
    bar();

    return;
}

function foo() {
    return;
}

This configuration would require blank lines after every sequence of variable declarations, like the newline-after-var rule.

该配置要求每一个变量声明之后都有空行，就像 newline-after-var 规则。

Examples of incorrect code for the [{ blankLine: "always", prev: ["const", "let", "var"], next: "*"}, { blankLine: "any", prev: ["const", "let", "var"], next: ["const", "let", "var"]}] configuration:

配置 [{ blankLine: "always", prev: ["const", "let", "var"], next: "*"}, { blankLine: "any", prev: ["const", "let", "var"], next: ["const", "let", "var"]}] 的 错误 代码示例：

/*eslint padding-line-between-statements: [
    "error",
    { blankLine: "always", prev: ["const", "let", "var"], next: "*"},
    { blankLine: "any",    prev: ["const", "let", "var"], next: ["const", "let", "var"]}
]*/

function foo() {
    var a = 0;
    bar();
}

function foo() {
    let a = 0;
    bar();
}

function foo() {
    const a = 0;
    bar();
}

Examples of correct code for the [{ blankLine: "always", prev: ["const", "let", "var"], next: "*"}, { blankLine: "any", prev: ["const", "let", "var"], next: ["const", "let", "var"]}] configuration:

配置 [{ blankLine: "always", prev: ["const", "let", "var"], next: "*"}, { blankLine: "any", prev: ["const", "let", "var"], next: ["const", "let", "var"]}] 的 正确 代码示例：

/*eslint padding-line-between-statements: [
    "error",
    { blankLine: "always", prev: ["const", "let", "var"], next: "*"},
    { blankLine: "any",    prev: ["const", "let", "var"], next: ["const", "let", "var"]}
]*/

function foo() {
    var a = 0;
    var b = 0;

    bar();
}

function foo() {
    let a = 0;
    const b = 0;

    bar();
}

function foo() {
    const a = 0;
    const b = 0;

    bar();
}

This configuration would require blank lines after all directive prologues, like the lines-around-directive rule.

该配置要所有的指令序言之后都有空行，就像 lines-around-directive 规则。

Examples of incorrect code for the [{ blankLine: "always", prev: "directive", next: "*" }, { blankLine: "any", prev: "directive", next: "directive" }] configuration:

配置 [{ blankLine: "always", prev: "directive", next: "*" }, { blankLine: "any", prev: "directive", next: "directive" }] 的 错误 代码示例：

/*eslint padding-line-between-statements: [
    "error",
    { blankLine: "always", prev: "directive", next: "*" },
    { blankLine: "any",    prev: "directive", next: "directive" }
]*/

"use strict";
foo();

Examples of correct code for the [{ blankLine: "always", prev: "directive", next: "*" }, { blankLine: "any", prev: "directive", next: "directive" }] configuration:

配置 [{ blankLine: "always", prev: "directive", next: "*" }, { blankLine: "any", prev: "directive", next: "directive" }] 的 正确 代码示例：

/*eslint padding-line-between-statements: [
    "error",
    { blankLine: "always", prev: "directive", next: "*" },
    { blankLine: "any",    prev: "directive", next: "directive" }
]*/

"use strict";
"use asm";

foo();

Compatibility

• JSCS: requirePaddingNewLineAfterVariableDeclaration
• JSCS: requirePaddingNewLinesAfterBlocks
• JSCS: disallowPaddingNewLinesAfterBlocks
• JSCS: requirePaddingNewLinesAfterUseStrict
• JSCS: disallowPaddingNewLinesAfterUseStrict
• JSCS: requirePaddingNewLinesBeforeExport
• JSCS: disallowPaddingNewLinesBeforeExport
• JSCS: requirePaddingNewlinesBeforeKeywords
• JSCS: disallowPaddingNewlinesBeforeKeywords

When Not To Use It

If you don’t want to notify warnings about linebreaks, then it’s safe to disable this rule.

如果你不想受到关于换行的通知，可以禁用此规则。

Version

This rule was introduced in ESLint 4.0.0-beta.0.

该规则在 ESLint 4.0.0-beta.0 中被引入。

Resources

• Rule source
• Documentation source