Question

I have a rather repetitive switch case statement and in my quest to learn the simplest way of doing things, I wanted to turn to SO and see if there is a more elegant solution to the following:

        switch(id)
        {
            case 'ib-02a':
                if(direction == 'left')
                    setHash('ib-02b');
                break;
            case 'ib-02b':
                if(direction == 'right')
                    setHash('ib-02a');
                if(direction == 'left')
                    setHash('ib-02c');
                break;
            case 'ib-02c':
                if(direction == 'right')
                    setHash('ib-02b');
                if(direction == 'left')
                    setHash('ib-02d');
                break;
            case 'ib-02d':
                if(direction == 'right')
                    setHash('ib-02c');
            break;

            case 'ib-03a':
                if(direction == 'left')
                    setHash('ib-03b');
                break;
            case 'ib-03b':
                if(direction == 'right')
                    setHash('ib-03a');
                if(direction == 'left')
                    setHash('ib-03c');
                break;
            case 'ib-03c':
                if(direction == 'right')
                    setHash('ib-03b');
                if(direction == 'left')
                    setHash('ib-03d');
                break;
            case 'ib-03d':
                if(direction == 'right')
                    setHash('ib-03c');
            break;

            case 'pb-05a':
                if(direction == 'left')
                    setHash('pb-05b');
                break;
            case 'pb-05b':
                if(direction == 'right')
                    setHash('pb-05a');
                if(direction == 'left')
                    setHash('pb-05c');
                break;
            case 'pb-05c':
                if(direction == 'right')
                    setHash('pb-05b');
                if(direction == 'left')
                    setHash('pb-05d');
                break;
            case 'pb-05d':
                if(direction == 'right')
                    setHash('pb-05c');
            break;
        }

I’m reading swipe events, and if the ID of the element I am swiping on matches either ib-02*, ib-03*, or pb-05*, I am calling a setHash function for the appropriate ID. If I’m swiping on *a, I swipe left to *b. If I’m swiping on *b, I swipe right to *a and left to *c. So on and so forth, always between *a and *d.

There must be a less repetitive way to do this, but I’m not sure exactly what the best approach is.

Answer 1

How about mapping them to an object? Then just use the setHash with the retrieved value.

var ids = {
    'pb-05c' : {
        left : 'pb-05d',
        right : 'pb-05b'
    }
    ...
}

function setHashes(id,direction){
    if(id && ids[id]){
        id = ids[id];
        if(direction && id[direction]){
            setHash(id[direction]);
        }
    }
}

It’s all retrieval and no condition evaluation, which can be good for performance.