Two callbacks separated by double pipes?

Question

Sorry for my possibly naive question, but I am totally novice to JavaScript.

I do not understand this:

return cordova.exec(success || onSuccess, fail || onFail, "Navigation", "exercise", [programId, levelId, orientation]);

The first two arguments are callbacks (success callback and failure callback),

but I do not understand: two callbacks separated by || like success || onSuccess ????

I am confused.

Thanks for your help.

If `success` doesn't exist, use `onSuccess`. There's some major uglIness there. — Denys Séguret, Jan 12 '15 at 16:14
Please use the search: [`[javascript] "||"`](http://stackoverflow.com/search?q=%5Bjavascript%5D+%22%7C%7C%22) — Felix Kling, Jan 12 '15 at 16:31

score 4 · Accepted Answer · answered Jan 12 '15 at 16:15

4

The || operand means "OR", that is, use the success callback if it exists, OR if it does not exist, use onSuccess.

answered Jan 12 '15 at 16:15

David Hughes

score 1 · Answer 2 · answered Jan 12 '15 at 16:27

success and onSuccess denotes the callback function (same case as fail and onFail)

so in their code their would be something like:

var success = function() { //some stuff here }

var onSuccess = function() { //some stuff apart from success function }

So it is if success function is not their use onSuccess (a fallback function to go to)

2 Answers2