Problem passing a wrapper class from LWC to Apex

Question

I am having trouble passing an apex wrapper class from LWC into APEX.

Apex

@AuraEnabled
public static void myMethod(SomeData theData) {
    system.debug('theData is ' + theData);
}

public class SomeData {
    public String theString;
    public Object theObject;
}

LWC

connectedCallback() {
    const myData= {
        'theString': 'Test',
        'theObject': true
    };
    myMethod({theData: myData})
    .then(result => {
        if (result) {
            
        }                   
    } catch(err) {
        
    }
}

When I run the code above what I get from APEX is [theString=null, theObject=null].

However if I modify the signature of the APEX method to be public static void myMethod(String theString, Object theObject) { and respectively pass that from the JS side myMethod({theString: myString, theObject: myObject}) where myString = 'Test'; and myObject = true that gets parsed properly in APEX and I can see it in the debugs.

I also tried specifying the sobjectType when instantiating the JS object like but that didn't help either:

const myData= {
    'sobjectType': 'SomeData',
    'theString': 'Test',
    'theObject': true
};

Answer 1

You need to @AuraEnable your attributes.

Incorrect

public class SomeData {
    public String theString;
    public Object theObject;

Correct

public class SomeData {
    @AuraEnabled public String theString { get; set; }
    @AuraEnabled public Object theObject { get; set; }
}