Searching through a javascript enum

Question

I have the following javascript enum:

// Rooms
var rooms = {
 1: 'First Room',
 2: 'Second Room',
 3: 'Third Room',
};

I can easily get the room description as follows:

// Get Room Description
var roomOne = 1;
var roomdesc = rooms[roomOne];

How about if I have the room description 'First Room' and I want to get the room number?

I tried:

// Get room number
var roomIndex = rooms.indexOf('First Room');
var roomNum = rooms[roomIndex];

But indexOf is undefined. How can I get the room number by room description?

Thanks

PS: Forgot to mention. I cannot change the rooms object. It is being used in other areas already! Also, I would like to do this without using prototype or jquery. Thanks.

Zee · Accepted Answer · 2015-05-26T16:09:42.950

2

Try this:

var rooms = {
    1: 'First Room',
    2: 'Second Room',
    3: 'Third Room',
};

function test(val){
 for (var key in rooms) {
   if(rooms.hasOwnProperty(key))
    if (rooms[key] == val) {
        alert("Key:"+key);
    }
 }
}
test('First Room');//Pass the value you want to search for

edited May 26 '15 at 16:09

answered May 26 '15 at 16:01

Zee

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You need to check `rooms.hasOwnProperty(key)` to assure you're accessing the correct object properties. – Rob Raisch May 26 '15 at 16:08
@RobertSmith. Forgot that part, updated thanks :) Robert Great :) – Zee May 26 '15 at 16:10

score 0 · Answer 2 · answered May 26 '15 at 15:55

0

I would suggest you to use Array's for this purposes:

var rooms = ['First Room','Second Room','Third Room'];
// Get Room Description
var roomOne = 0;
var roomdesc = rooms[roomOne];
// Get room number
var roomIndex = rooms.indexOf('First Room');
var roomNum = rooms[roomIndex];

console.log( roomNum )

Not that Arrays are zero-first indexed.

answered May 26 '15 at 15:55

antyrat

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Thanks but, Sorry forgot to mention the rooms object cannot be changed. It is already being used in other places. – Robert Smith May 26 '15 at 15:57
@RobertSmith but you can iterate over it anyway, do you? – antyrat May 26 '15 at 15:58

Frank Adrian · Answer 3 · 2015-05-26T16:13:09.097

-3

Try this:

var test = {
    1: 'First Room',
    2: 'Second Room',
    3: 'Third Room',
};
function getKeyByValue (obj, value) {
    for( var prop in obj ) {
        if( obj.hasOwnProperty( prop ) ) {
             if( obj[ prop ] === value )
                 return prop;
        }
    }
}
console.log(getKeyByValue( test, "Second Room" ));  // logs 2

edited May 26 '15 at 16:13

answered May 26 '15 at 15:57

Frank Adrian

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Copying an answer from another question is not really constructive. – Rob Raisch May 26 '15 at 16:01
What is the purpose to copy-paste answers from [other questions](http://stackoverflow.com/questions/9907419/javascript-object-get-key-by-value) rather than writing your own or point to that answers? – antyrat May 26 '15 at 16:01
Thanks, but is there a simpler 2 or 3 line solution without using Object.prototype? – Robert Smith May 26 '15 at 16:03
Well you can simply write a for loop on the Object, check if it hasOwnProperty and return the value. (Updated answer) – Frank Adrian May 26 '15 at 16:09

Searching through a javascript enum

3 Answers3