Enforce spacing before and after semicolons (semi-spacing)

JavaScript allows you to place unnecessary spaces before or after a semicolon.

Disallowing or enforcing space around a semicolon can improve the readability of your program.

var a = "b" ;

var c = "d";var e = "f";

Rule Details

This rule aims to enforce spacing around a semicolon. This rule prevents the use of spaces before a semicolon in expressions.

Options

The rule takes one option, an object, which has two keys before and after having boolean values true or false. If before is true, space is enforced before semicolons and if it’s false, space is disallowed before semicolons. If after is true, space is enforced after semicolons and if it’s false, space is disallowed after semicolons. The after option will be only applied if a semicolon is not at the end of line.

The default is {"before": false, "after": true}.

    "semi-spacing": [2, {"before": false, "after": true}]

{“before”: false, “after”: true}

This is the default option. It enforces spacing after semicolons and disallows spacing before semicolons.

The following patterns are considered warnings:

var foo ;
var foo;var bar;
throw new Error("error") ;
while (a) { break ; }
for (i = 0 ; i < 10 ; i++) {}
for (i = 0;i < 10;i++) {}

The following patterns are not warnings:

var foo;
var foo; var bar;
throw new Error("error");
while (a) { break; }
for (i = 0; i < 10; i++) {}

{“before”: true, “after”: false}

This option enforces spacing before semicolons and disallows spacing after semicolons.

The following patterns are considered warnings:

var foo;
var foo ; var bar;
throw new Error("error");
while (a) { break; }
for (i = 0;i < 10;i++) {}
for (i = 0; i < 10; i++) {}

The following patterns are not warnings:

var foo ;
var foo ;var bar;
throw new Error("error") ;
while (a) {break ;}
for (i = 0 ;i < 10 ;i++) {}

When Not To Use It

You can turn this rule off if you are not concerned with the consistency of spacing before or after semicolons.

Version

This rule was introduced in ESLint 0.16.0.