Disallow ++ and – (no-plusplus)

The no-plusplus rule flags the use of unary operators, ++ and --.

var foo = 0;
foo++;

The ++ and -- operators are subject to automatic semicolon insertion. When their use is allowed, introducing whitespace may change semantics of source code. Enabling the rule may prevent this kind of errors.

var i = 10;
var j = 20;

i ++
j
// i = 11, j = 20

var i = 10;
var j = 20;

i
++
j
// i = 10, j = 21

Rule Details

This rule is aimed at flagging the use of ++ and --. Some believe that the use of these unary operators reduces code quality and clarity. There are some programming languages that completely exclude these operators.

The following patterns are considered warnings:

var foo = 0;
foo++;

var bar = 42;
bar--;

The following patterns are not considered warnings:

var foo = 0;
foo += 1;

var bar = 42;
bar -= 1;

Version

This rule was introduced in ESLint 0.0.9.

Resources