How to validate using nested models/detect if code is running server side or client side?

[stephaniesyed]

I have a validation function that needs to get info on nested data to validate:

 validate: async (val, {data, siblingData}) => {
            console.log('siblingData 1', siblingData)
            if (val === undefined) {
                return "Shipper Location is required"
            }

            // console.log(siblingData)
            // const response = await fetch(`${apiUrl}shipperLocations/${val}`).then(res => res.json())    
            // console.log(response)
            // if(response.partner.id !== siblingData.partner) {
            //     return "Shipper Location must be from the same partner"
            // }
            // return true
            // console.log(response)
            // console.log('siblingData 2', siblingData)
            if (payload.length === 0) {
                console.log('payload is undefined')
            }

            // console.log('siblingData 3', siblingData)

            // return "this is the worst"
            // console.log('shipperLocation validate')
            // // console.log('val', val)
            // // console.log(' val type', typeof val)
            // console.log('siblingData', siblingData)
            // console.log('data', data)
            // // console.log('siblingData.partner', siblingData.partner)
            // // console.log('payload', payload)
            // // console.log('payload', Object.getOwnPropertyNames(payload))
            // // console.log('payload length', payload.length)
            // // console.log('payload name', payload.name)

            const shipperLocation = await payload.findByID({
                collection: 'shipperLocations',
                id: val,
            });
            console.log('shipperLocation', shipperLocation)
            console.log('siblingData.partner', siblingData.partner)
            if(shipperLocation.partner.id !== siblingData.partner) {
                return "Shipper Location must be from the same partner"
            }
            return true
        },

Essentially, when running client side, payload isn't populated as described in the documentation. Ideally, for server side validation I want to use the local API, but I can't use that client side. Is there an established pattern for defining functionality differently depending on where the code is executing? That seems like a common problem others would have run into.

I can define the method like this:

validate: async (val, { data, siblingData }) => {
        if (val === undefined) {
          return "Shipper Location is required";
        }
        if (payload.length === 0) {
          // payload isn't correctly populated client side
          const response = await fetch(`${apiUrl}shipperLocations/${val}`).then(
            (res) => res.json()
          );
          if (response.partner.id !== siblingData.partner) {
            return "Shipper Location must be from the same partner";
          }
          return true;
        }

        //serverside can use the local API to query data
        const shipperLocation = await payload.findByID({
          collection: "shipperLocations",
          id: val,
        });
        if (shipperLocation.partner.id !== siblingData.partner) {
          return "Shipper Location must be from the same partner";
        }
        return true;
      },
    },

but that check feels brittle