Require or disallow an newline around variable declarations (one-var-declaration-per-line)
Some developers declare multiple var statements on the same line:
var foo, bar, baz = 0;
Others prefer to declare one var per line.
var foo,
bar,
baz = 0;
This rule enforces a consistent style across the entire project.
Rule Details
This rule enforces a consistent coding style where newlines are required or disallowed after each var declaration or just when there is a variable initialization. It ignores var declarations inside for loop conditionals.
Options
This rule takes one option, a string, which can be:
"always"
enforces a newline around each variable declaration (default)"initializations"
enforces a newline around a variable initialization
The following patterns are considered problems when set to "always"
:
/*eslint one-var-declaration-per-line: [2, "always"]*/
/*eslint-env es6*/
var a, b; /*error Expected variable declaration to be on a new line. */
let a, b = 0; /*error Expected variable declaration to be on a new line. */
const a = 0, b = 0; /*error Expected variable declaration to be on a new line. */
The following patterns are not considered problems when set to "always"
:
/*eslint one-var-declaration-per-line: [2, "always"]*/
/*eslint-env es6*/
var a,
b;
let a,
b = 0;
The following patterns are considered problems when set to "initializations"
:
/*eslint one-var-declaration-per-line: [2, "initializations"]*/
/*eslint-env es6*/
var a, b, c = 0; /*error Expected variable declaration to be on a new line. */
let a,
b = 0, c; /*error Expected variable declaration to be on a new line. */
The following patterns are not considered problems when set to "initializations"
:
/*eslint one-var-declaration-per-line: [2, "initializations"]*/
/*eslint-env es6*/
var a, b;
let a,
b;
let a,
b = 0;
Related Rules
Version
This rule was introduced in ESLint 2.0.0-beta.3.