no-arrow-condition

Disallows arrow functions where test conditions are expected.

Arrow functions (=>) are similar in syntax to some comparison operators (>, <, <=, and >=). This rule warns against using the arrow function syntax in places where a condition is expected. Even if the arguments of the arrow function are wrapped with parens, this rule still warns about it.

Here’s an example where the usage of => is most likely a typo:

// This is probably a typo
if (a => 1) {}
// And should instead be
if (a >= 1) {}
1
2
3
4

There are also cases where the usage of => can be ambiguous and should be rewritten to more clearly show the author’s intent:

// The intent is not clear
var x = a => 1 ? 2 : 3
// Did the author mean this
var x = function (a) { return a >= 1 ? 2 : 3 }
// Or this
var x = a <= 1 ? 2 : 3
1
2
3
4
5
6

Rule Details

Examples of incorrect code for this rule:

/*eslint no-arrow-condition: "error"*/

if (a => 1) {}
while (a => 1) {}
for (var a = 1; a => 10; a++) {}
a => 1 ? 2 : 3
(a => 1) ? 2 : 3
var x = a => 1 ? 2 : 3
var x = (a) => 1 ? 2 : 3
1
2
3
4
5
6
7
8
9

Related Rules

• arrow-parens
• no-confusing-arrow
• no-constant-condition

Version

This rule was introduced in ESLint v1.8.0 and removed in v2.0.0-beta.3.