Can't set NULL for Enum properties in Structs and Messages

[vladmu]

Based on the condition below the keyForValue call based on the default Enum's _keyForValue will always return null here for null obj

sdl_javascript_suite/lib/js/src/rpc/RpcStruct.js

Lines 141 to 146 in 1e0e6be

	} else if (
	(tClass.prototype instanceof Enum && tClass.keyForValue(obj) === null)
	|| (tClass.prototype instanceof RpcStruct && obj !== null && obj.constructor !== tClass)
	) {
	throw new Error(`${obj.name} must be of type ${tClass.name}`);
	}

Then because the condition is true, the code fails in line 145 with the error

TypeError: Cannot read property 'name' of null

Currently, all Enum classes use default _keyForValue for checks in their keyForValue methods so it is impossible to set null for all Enum properties (mandatory or optional) in all Structs and Messages

Steps to reproduce:

1. Create for example the new instance of KeyboardProperties structure
2. Try to set KeyboardLayout parameter (according to the spec this parameter is not mandatory) by calling setKeyboardLayout method with null value
3. ER: null is successfully set, AR: the TypeError

new SDL.rpc.structs.KeyboardProperties().setKeyboardLayout(null) // this fails with TypeError: Cannot read property 'name' of null

[vladmu]

Possible solution is to skip null value for Enum the same way as for RpcStruct

 } else if ( 
    obj !== null && (
        (tClass.prototype instanceof Enum && tClass.keyForValue(obj) === null) 
        || (tClass.prototype instanceof RpcStruct && obj.constructor !== tClass) 
    )
 ) { 
     throw new Error(`${obj.name} must be of type ${tClass.name}`); 
 }