array search / for loop

Question

I've currently got a implementation which loops through an array within a json document (returned from mongoose) and looks for specific items as below

So what's happening is i'm passing an id in the request header to express and what i need to happen is for it to grab the associated story.users.id.name from the story.users array is returned and then once it has the name send do something with all the other items in the array.

I did try to do this like below:

            for (var i = 0; i < story.users.length; i++) {
                if (story.users[i].id._id == req.headers.id) {
                   var name = story.users[i].id.name
                } else {
                    push.apns(story.users[i].id._id, name + " started a new story");
                }
            }

Where it would loop through grab the name and then do something with all the other users in the array, however sometimes the else argument fires first so the name variable is undefined.

So i resorted to running two if loops after each other like below:

            for (var i = 0; i < story.users.length; i++) {
                if (story.users[i].id._id == req.headers.id) {
                    var name = story.users[i].id.name
                }
            };
            for (var i = 0; i < story.users.length; i++) {
                if (story.users[i].id._id == req.headers.id) {
                } else {
                    push.apns(story.users[i].id._id, name + " started a new story");
                }
            }

But there must be a better way to the above rather than looping through an array twice?

Denys Séguret · Accepted Answer · 2013-08-25 13:17:08Z

2

What you do looks like the right solution (with the goal you seem to have). There's no real simple way to do only one loop.

You could make it faster and cleaner, though :

var name; // this is just cleaner than to define it in the loop
for (var i = 0; i < story.users.length; i++) {
    if (story.users[i].id._id == req.headers.id) {
        name = story.users[i].id.name;
        break; // don't loop over the other elements
    }
};
for (var i = 0; i < story.users.length; i++) {
    if (story.users[i].id._id !== req.headers.id) {
        push.apns(story.users[i].id._id, name + " started a new story");
    }
}

answered Aug 25, 2013 at 13:17

community wiki

Denys Séguret

Sign up to request clarification or add additional context in comments.

1 Comment

Tam2 Over a year ago

Thanks, I've updated my code to go with this cleaner way of doing it

Collectives™ on Stack Overflow

array search / for loop

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related