Why avoid increment ("++") and decrement ("--") operators in JavaScript?

javascript syntax jslint postfix-operator prefix-operator
artlung picture artlung · Jun 9, 2009 · Viewed 335.9k times · Source

One of the tips for jslint tool is:

++ and --
The ++ (increment) and -- (decrement) operators have been known to contribute to bad code by encouraging excessive trickiness. They are second only to faulty architecture in enabling to viruses and other security menaces. There is a plusplus option that prohibits the use of these operators.

I know that PHP constructs like $foo[$bar++] has may easily result with off-by-one errors, but I couldn't figure out a better way to control the loop than a while( a < 10 ) do { /* foo */ a++; } or for (var i=0; i<10; i++) { /* foo */ }.

Is the jslint highlighting them because there are some similar languages that lack the "++" and "--" syntax or handle it differently, or are there other rationales for avoiding "++" and "--" that I might be missing?

Answer

cdmckay picture cdmckay · Jun 9, 2009

My view is to always use ++ and -- by themselves on a single line, as in:

i++;
array[i] = foo;

instead of

array[++i] = foo;

Anything beyond that can be confusing to some programmers and is just not worth it in my view. For loops are an exception, as the use of the increment operator is idiomatic and thus always clear.

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