JS.BASE.PADDED.BLOCKS

Require or disallow padding within blocks

Some style guides require block statements to start and end with blank lines. The goal is to improve readability by visually separating the block content and the surrounding code.

Copy
if (a) {

    b();

}

Since it's good to have a consistent code style, you should either always write padded blocks or never do it.

Rule Details

This rule enforces consistent empty line padding within blocks.

Options

This rule has two options, the first one can be a string option or an object option. The second one is an object option, it can allow exceptions.

First option

String option:

  • "always" (default) requires empty lines at the beginning and ending of block statements, function bodies, class static blocks, classes, and switch statements.
  • "never" disallows empty lines at the beginning and ending of block statements, function bodies, class static blocks, classes, and switch statements.

Object option:

  • "blocks" require or disallow padding within block statements, function bodies, and class static blocks
  • "classes" require or disallow padding within classes
  • "switches" require or disallow padding within switch statements

Second option

  • "allowSingleLineBlocks": true allows single-line blocks

always

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

Copy
/*eslint padded-blocks: ["error", "always"]*/

if (a) {
    b();
}

if (a) { b(); }

if (a)
{
    b();
}

if (a) {
    b();

}

if (a) {
    // comment
    b();

}

class C {
    static {
        a();
    }
}

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

Copy
/*eslint padded-blocks: ["error", "always"]*/

if (a) {

    b();

}

if (a)
{

    b();

}

if (a) {

    // comment
    b();

}

class C {

    static {

        a();

    }

}

never

Examples of incorrect code for this rule with the "never" option:

Copy
/*eslint padded-blocks: ["error", "never"]*/

if (a) {

    b();

}

if (a)
{

    b();

}

if (a) {

    b();
}

if (a) {
    b();

}

class C {

    static {

        a();

    }

}

Examples of correct code for this rule with the "never" option:

Copy
/*eslint padded-blocks: ["error", "never"]*/

if (a) {
    b();
}

if (a)
{
    b();
}

class C {
    static {
        a();
    }
}

blocks

Examples of incorrect code for this rule with the { "blocks": "always" } option:

Copy
/*eslint padded-blocks: ["error", { "blocks": "always" }]*/

if (a) {
    b();
}

if (a) { b(); }

if (a)
{
    b();
}

if (a) {

    b();
}

if (a) {
    b();

}

if (a) {
    // comment
    b();

}

class C {

    static {
        a();
    }

}

Examples of correct code for this rule with the { "blocks": "always" } option:

Copy
/*eslint padded-blocks: ["error", { "blocks": "always" }]*/

if (a) {

    b();

}

if (a)
{

    b();

}

if (a) {

    // comment
    b();

}

class C {

    static {

        a();

    }

}

class D {
    static {

        a();

    }

}

Examples of incorrect code for this rule with the { "blocks": "never" } option:

Copy
/*eslint padded-blocks: ["error", { "blocks": "never" }]*/

if (a) {

    b();

}

if (a)
{

    b();

}

if (a) {

    b();
}

if (a) {
    b();

}

class C {
    static {

        a();

    }
}

Examples of correct code for this rule with the { "blocks": "never" } option:

Copy
/*eslint padded-blocks: ["error", { "blocks": "never" }]*/

if (a) {
    b();
}

if (a)
{
    b();
}

class C {
    static {
        a();
    }
}

class D {

    static {
        a();
    }

}

classes

Examples of incorrect code for this rule with the { "classes": "always" } option:

Copy
/*eslint padded-blocks: ["error", { "classes": "always" }]*/

class  A {
    constructor(){
    }
}

Examples of correct code for this rule with the { "classes": "always" } option:

Copy
/*eslint padded-blocks: ["error", { "classes": "always" }]*/

class  A {

    constructor(){
    }

}

Examples of incorrect code for this rule with the { "classes": "never" } option:

Copy
/*eslint padded-blocks: ["error", { "classes": "never" }]*/

class  A {

    constructor(){
    }

}

Examples of correct code for this rule with the { "classes": "never" } option:

Copy
/*eslint padded-blocks: ["error", { "classes": "never" }]*/

class  A {
    constructor(){
    }
}

switches

Examples of incorrect code for this rule with the { "switches": "always" } option:

Copy
/*eslint padded-blocks: ["error", { "switches": "always" }]*/

switch (a) {
    case 0: foo();
}

Examples of correct code for this rule with the { "switches": "always" } option:

Copy
/*eslint padded-blocks: ["error", { "switches": "always" }]*/

switch (a) {

    case 0: foo();

}

if (a) {
    b();
}

Examples of incorrect code for this rule with the { "switches": "never" } option:

Copy
/*eslint padded-blocks: ["error", { "switches": "never" }]*/

switch (a) {

    case 0: foo();

}

Examples of correct code for this rule with the { "switches": "never" } option:

Copy
/*eslint padded-blocks: ["error", { "switches": "never" }]*/

switch (a) {
    case 0: foo();
}

if (a) {

    b();

}

always + allowSingleLineBlocks

Examples of incorrect code for this rule with the "always", {"allowSingleLineBlocks": true} options:

Copy
/*eslint padded-blocks: ["error", "always", { allowSingleLineBlocks: true }]*/

if (a) {
    b();
}

if (a) {

    b();
}

if (a) {
    b();

}

Examples of correct code for this rule with the "always", {"allowSingleLineBlocks": true} options:

Copy
/*eslint padded-blocks: ["error", "always", { allowSingleLineBlocks: true }]*/

if (a) { b(); }

if (a) {

    b();

}

When Not To Use It

You can turn this rule off if you are not concerned with the consistency of padding within blocks.

The content on this page is adapted from the ESLint User Guide. Copyright © OpenJS Foundation and other contributors, www.openjsf.org. All rights reserved. https://eslint.org/docs/rules/