async-or

Run tasks in parallel, and take the result from either the first (by list-order) task that succeeds, or, if none succeed, the last tasks error.

Usage

pass an array of tasks that take a callback as their first parameter, and a callback:

 
function works1(done){
    setTimeout(function(){
        done(null, 1);
    }, 100);
}
 
function works2(done){
    setTimeout(function(){
        done(null, 2);
    }, 200);
}
 
asyncOr([works1, works2], function(error, result){
    error; // -> null
    result; // -> 1
});
 

Tasks are run in parallel, and the first task in the task list that succeeds will resolve the callback.

eg:

given tasks: [a, b, c]

• if a succeeds, it will resolve the callback.

• if a fails, and b succeeds, b will resolve the callback.

• if a, b, and c fail, the callback will be resolved with c's error.

• The chronological order in which tasks complete has no impact on which task will resolve the callback. *

See the tests for a more in-depth explaination of cases.