W3cubDocs

/ESLint

Require space before/after arrow function's arrow (arrow-spacing)

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

This rule normalize style of spacing before/after an arrow function's arrow(=>).

/*eslint-env es6*/

// { "before": true, "after": true }
(a) => {}

// { "before": false, "after": false }
(a)=>{}

This rule takes an object argument with before and after properties, each with a Boolean value.

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

true means there should be one or more spaces and false means no spaces.

Examples of incorrect code for this rule with the default { "before": true, "after": true } option:

/*eslint arrow-spacing: "error"*/
/*eslint-env es6*/

()=> {};
() =>{};
(a)=> {};
(a) =>{};
a =>a;
a=> a;
()=> {'\n'};
() =>{'\n'};

Examples of correct code for this rule with the default { "before": true, "after": true } option:

/*eslint arrow-spacing: "error"*/
/*eslint-env es6*/

() => {};
(a) => {};
a => a;
() => {'\n'};

Examples of incorrect code for this rule with the { "before": false, "after": false } option:

/*eslint arrow-spacing: ["error", { "before": false, "after": false }]*/
/*eslint-env es6*/

() =>{};
(a) => {};
()=> {'\n'};

Examples of correct code for this rule with the { "before": false, "after": false } option:

/*eslint arrow-spacing: ["error", { "before": false, "after": false }]*/
/*eslint-env es6*/

()=>{};
(a)=>{};
()=>{'\n'};

Examples of incorrect code for this rule with the { "before": false, "after": true } option:

/*eslint arrow-spacing: ["error", { "before": false, "after": true }]*/
/*eslint-env es6*/

() =>{};
(a) => {};
()=>{'\n'};

Examples of correct code for this rule with the { "before": false, "after": true } option:

/*eslint arrow-spacing: ["error", { "before": false, "after": true }]*/
/*eslint-env es6*/

()=> {};
(a)=> {};
()=> {'\n'};

This rule was introduced in ESLint 1.0.0-rc-1.