lines-around-directive

Require or disallow newlines around directives

🔧

Some problems reported by this rule are automatically fixable by the --fix command line option

此规则在 ESLint v4.0.0 中被 padding-line-between-statements 规则所取代，并被废弃。

在 JavaScript 中，指令被用来向执行环境表明一个脚本希望选择 "strict mode" 这样的特性。指令被分组在文件或函数块顶部的 directive prologue 中，并被应用到它们出现的范围中。

// Strict mode is invoked for the entire script
"use strict";

var foo;

function bar() {
  var baz;
}
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var foo;

function bar() {
  // Strict mode is only invoked within this function
  "use strict";

  var baz;
}
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规则细节

这条规则要求或不允许在指令的序言部分使用空白换行。这条规则并不强制执行关于各个指令之间的空白换行的任何约定。此外，它也不要求指令序言前的空白换行，除非它们前面有注释。如果你想执行这种风格，请使用 padded-blocks 规则。

选项

这个规则有一个选项。它可以是一个字符串，也可以是一个对象：

"always"（默认值）执行指令周围的空白换行。
"never"不允许指令周围有空白的新行。

或

{
  "before": "always" or "never"
  "after": "always" or "never",
}
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always

这是默认的选项。

使用此规则与 "always" 选项的错误示例：

Open in Playground

/* eslint lines-around-directive: ["error", "always"] */

/* Top of file */
"use strict";
var foo;

/* Top of file */
// comment
"use strict";
"use asm";
var foo;

function foo() {
  "use strict";
  "use asm";
  var bar;
}

function foo() {
  // comment
  "use strict";
  var bar;
}
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使用此规则与 "always" 选项的正确示例：

Open in Playground

/* eslint lines-around-directive: ["error", "always"] */

/* Top of file */
"use strict";

var foo;

/* Top of file */
// comment

"use strict";
"use asm";

var foo;

function foo() {
  "use strict";
  "use asm";

  var bar;
}

function foo() {
  // comment

  "use strict";

  var bar;
}
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never

使用此规则与 "never" 选项的错误示例：

Open in Playground

/* eslint lines-around-directive: ["error", "never"] */

/* Top of file */

"use strict";

var foo;

/* Top of file */
// comment

"use strict";
"use asm";

var foo;

function foo() {
  "use strict";
  "use asm";

  var bar;
}

function foo() {
  // comment

  "use strict";

  var bar;
}
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使用此规则与 "never" 选项的正确示例：

Open in Playground

/* eslint lines-around-directive: ["error", "never"] */

/* Top of file */
"use strict";
var foo;

/* Top of file */
// comment
"use strict";
"use asm";
var foo;

function foo() {
  "use strict";
  "use asm";
  var bar;
}

function foo() {
  // comment
  "use strict";
  var bar;
}
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before & after

使用此规则与 { "before": "never", "after": "always" } 选项的错误示例：

Open in Playground

/* eslint lines-around-directive: ["error", { "before": "never", "after": "always" }] */

/* Top of file */

"use strict";
var foo;

/* Top of file */
// comment

"use strict";
"use asm";
var foo;

function foo() {
  "use strict";
  "use asm";
  var bar;
}

function foo() {
  // comment

  "use strict";
  var bar;
}
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使用此规则与 { "before": "never", "after": "always" } 选项的正确示例：

Open in Playground

/* eslint lines-around-directive: ["error", { "before": "never", "after": "always" }] */

/* Top of file */
"use strict";

var foo;

/* Top of file */
// comment
"use strict";
"use asm";

var foo;

function foo() {
  "use strict";
  "use asm";

  var bar;
}

function foo() {
  // comment
  "use strict";

  var bar;
}
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使用此规则与 { "before": "always", "after": "never" } 选项的错误示例：

Open in Playground

/* eslint lines-around-directive: ["error", { "before": "always", "after": "never" }] */

/* Top of file */
"use strict";

var foo;

/* Top of file */
// comment
"use strict";
"use asm";

var foo;

function foo() {
  "use strict";
  "use asm";

  var bar;
}

function foo() {
  // comment
  "use strict";

  var bar;
}
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使用此规则与 { "before": "always", "after": "never" } 选项的正确示例：

Open in Playground

/* eslint lines-around-directive: ["error", { "before": "always", "after": "never" }] */

/* Top of file */
"use strict";
var foo;

/* Top of file */
// comment

"use strict";
"use asm";
var foo;

function foo() {
  "use strict";
  "use asm";
  var bar;
}

function foo() {
  // comment

  "use strict";
  var bar;
}
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何时不用

如果你对指令性序言前后是否应该有空白换行没有任何严格的约定，你可以安全地禁用这一规则。

兼容

JSCS：requirePaddingNewLinesAfterUseStrict
JSCS：disallowPaddingNewLinesAfterUseStrict

Version

This rule was introduced in ESLint v3.5.0.

Resources

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lines-around-directive

规则细节

选项

always

never

before & after

何时不用

兼容

Related Rules

Version

Resources