Checking defined item in enum

Question

I have an enum in which I store some UI element values that look like this:

const uiElementAttributes = {
   1: {
      id: 1,
      color: 'red',
      icon: 'icon-something.png'
   },
   2: {
      id: 2,
      color: 'yellow',
      icon: 'icon-something-else.png'
   },
   3: {
      id: 3,
      color: 'blue',
      icon: 'icon-this-item.png'
   },
   99: {
      id: 99,
      color: 'black',
      icon: 'icon-black.png'
   }
};

I have a function that will return the correct object from the enum based on id passed to my function. My question is how do I check if a value is defined in an enum?

Here's the function:

const getAttributes (id) => {

   // How do I check to see if the id is in the enum?
   if(checkIfIdIsInEnum) {
      return uiElementAttributes[id];
   } else {
      return uiElementAttributes[99];
   }

};

UPDATE: I'm trying the suggested answer. It does look pretty straight forward but looks like when webpack transpiles my code to vanilla JS, it adds default at the end of my enum which is undefined. Any idea what may be causing this -- see below? As you can see, the id value I'm passing is 1 so it should be able to find the value 1 in my enum object.

And here's the actual enum object:

Here's the actual function code:

UPDATE 2: I resolved the issue by importing the enum within curly braces -- see below:

import {calendarEvents} from '../../enums/calendarEvents';

So `if(uiElementAttributes.hasOwnProperty(id)){ /*it exists*/}` — E. Sundin, Jul 18 '17 at 17:53

score 1 · Accepted Answer · answered Jul 18 '17 at 17:55

1

In this special case, you could access the property and if the result is falsey, then take the default property 99.

const getAttributes = id => uiElementAttributes[id] || uiElementAttributes[99];

Otherwise, you could use the in operator, or the suggested Object#hasOwnProperty.

answered Jul 18 '17 at 17:55

Nina Scholz

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I'm using this suggested solution which seems pretty straight forward but I'm getting an error. Please see the UPDATE I've added to the original post. – Sam Jul 18 '17 at 18:20
it depends on the data structure, which is not viewable at the image. – Nina Scholz Jul 18 '17 at 18:24
Just updated the original post with a screen shot of the `enum` object. – Sam Jul 18 '17 at 18:26
In the actual code, my default value will come from object 0. – Sam Jul 18 '17 at 18:27
i see `calendarEvents` and not `calendarEvents2` without any default property. – Nina Scholz Jul 18 '17 at 18:28
Not sure why it becomes `calendarEvents2`. I just posted the actual code of the function. – Sam Jul 18 '17 at 18:32
Looks like the `default` is what's messing things up. Not sure why my `enum` object gets renamed to `CalendarEvents2` and `default` is appended to the name. – Sam Jul 18 '17 at 18:39
i have no idea either. – Nina Scholz Jul 18 '17 at 18:42
1

I resolved it. See UPDATE 2. Thank you for your help! – Sam Jul 18 '17 at 18:43

Checking defined item in enum

1 Answers1