CODEWITHSUNDEEP
javascriptlookup
dibs
dibs

Reputation: 1077

Is there a better way to write this javascript?

Is there a better way to write this JavaScript?

switch (l) {
    //A
    case '1-1-1':
    case '1-1-2':
    case '1-2-1':
    case '2-1-1':
    case '3-1-1':
        obj.result = 'A';
        break;
    //B
    case '1-2-2':
    case '1-2-3':
    case '2-2-2':
    case '2-2-3':
    case '3-2-2':
    case '3-3-1':
        obj.result = 'B';
        break;
    //C
    case '1-3-2':
    case '1-3-3':
    case '2-3-2':
    case '3-2-3':
        obj.result = 'C';
        break;
    //D
    case '3-3-2':
    case '3-3-3':
        obj.result = 'D';
        break;
    default:
        obj.result = 'AA';
        break;
}

Upvotes: 0

Views: 111

Answers (3)

nnnnnn
nnnnnn

Reputation: 150080

Encapsulate the number to letter processing in a function so that your main code doesn't need to know how the translation is done. Call it like this:

obj.result = getThing(l);

// or, given your comment that l is formed by concatenating three
// values you could do the concatenation in the function
obj.result = getThing(v1, v2, v3);

Then within getThing() you can use your existing switch statement, or the lookup table from Matt Ball's answer, or whatever other method you like. And you can change the method at any time with no impact on the code that calls the function.

function getThing(v1, v2, v3) {
   var l = v1 + "-" + v2 + "-" + v3;
   // use lookup, switch, whatever
   return "somecode";
}

Note: don't actually call your function "getThing"; replace "Thing" with something that describes whatever these letter codes really are.

Upvotes: 0

Matt Ball
Matt Ball

Reputation: 359966

The lookup table, as mentioned by Thilo in the comments:

var lookup =
{
    '1-1-1': 'A',
    '1-1-2': 'A',
    '1-2-1': 'A',
    '2-1-1': 'A',
    '3-1-1': 'A',

    '1-2-2': 'B',
    '1-2-3': 'B',
    '2-2-2': 'B',
    '2-2-3': 'B',
    '3-2-2': 'B',
    '3-3-1': 'B',

    '1-3-2': 'C',
    '1-3-3': 'C',
    '2-3-2': 'C',
    '3-2-3': 'C',
    '3-3-2': 'C',

    '3-3-3': 'D'
};

and its usage:

obj.result = lookup[l] || 'AA';

I can't say this is really any better than the switch version.

Upvotes: 1

icktoofay
icktoofay

Reputation: 129109

If you told us how you got those values, we might be able to come up with a more concise solution, but here's how you'd use a lookup table (generated kind of backwards):

var byResult={
    A: ['1-1-1', '1-1-2', /* ... */],
    B: ['1-2-2', '1-2-3', /* ... */],
    /* ... */
};
var byInput={};
for(var output in byResult) {
    if(!Object.prototype.hasOwnProperty.call(byResult, output)) {
        continue;
    }
    var inputs=byResult[output];
    for(var i=0, l=inputs.length; i<l; i++) {
        var input=inputs[i];
        byInput[input]=output;
    }
}
function lookup(value) {
    if(Object.prototype.hasOwnProperty.call(byInput, value)) {
        return byInput[value];
    }else{
        return 'AA';
    }
}

Upvotes: 1

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