How to use `enum` with `ffi`?

Hi! I’m working on a project that integrates a shared C library with Node. I’m using the ffi module for this which, in turn, uses the ref library for types. I’ve seen that @TooTallNate did a PR awhile back to implement the type interface so this could be used with ref. I can’t, for the life of me, figure out how to get this to work. Full disclosure: I’m not a C programmer at all.

Here’s the enum definition in the C code:

typedef enum {
    DEVICE_UNKNOWN,
    DEVICE_IOS_IPHONE,
    DEVICE_IOS_IPOD,
    DEVICE_IOS_IPAD,
    DEVICE_WINDOWS_PC,
    DEVICE_WINDOWS_PHONE,
    DEVICE_WINDOWS_TABLET,
    DEVICE_MAC
} E_DEVICE_TYPE;

There is a method called SetDeviceType that accepts DEVICE_MAC as it’s input parameter. In my Javascript I’ve done the following:

const deviceTypeEnum = new Enum([
  'DEVICE_UNKNOWN',
  'DEVICE_IOS_IPHONE',
  'DEVICE_IOS_IPOD',
  'DEVICE_IOS_IPAD',
  'DEVICE_WINDOWS_PC',
  'DEVICE_WINDOWS_PHONE',
  'DEVICE_WINDOWS_TABLET',
  'DEVICE_MAC',
], { name: 'E_DEVICE_TYPE' });

I’ve also tried:

const deviceTypeEnum = new Enum({
  DEVICE_UNKNOWN: 0,
  DEVICE_IOS_IPHONE: 1,
  DEVICE_IOS_IPOD: 2,
  DEVICE_IOS_IPAD: 3,
  DEVICE_WINDOWS_PC: 4,
  DEVICE_WINDOWS_PHONE: 5,
  DEVICE_WINDOWS_TABLET: 6,
  DEVICE_MAC: 7,
}, { name: 'E_DEVICE_TYPE' });

I then call my function (defined on ffi) like so:

this.client.setDeviceType(deviceTypeEnum.DEVICE_MAC);

and also tried:

this.client.setDeviceType(deviceTypeEnum.DEVICE_MAC.value);

On the ffi definition I’ve tried setting the parameter type as int and uint32. Unfortunately, this doesn’t seem to be setting the correct value in the C library. Can anyone see if I’m missing something? It’s probably something obvious but I’ve been bashing my head against this for a couple of days and thought I’d reach out for assistance. Thanks for any help you might be able to provide!

[goel-sunny]

no need of defining enum in your javascript code , but at the place of enum define an int variable , so at the time of passing of argument pass only an integer value to the dll , dll at backend will accept this .

[adrai]

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