How to send flattened data from Javascript file of LWC to Apex method?

Question

I get data from a wrapper class and flatten the data in JS file of my LWC as follows:

 @wire(getAccount, { id: '$recordId' }) wired(result) {
        this.refreshTable = result;
        if (result.data) {
            //create an array
            let preparedAccounts = [];
            //use for each loop and put one row at a time in variable named account
            result.data.forEach(account => {
                //create a row and add data
                let preparedAccount = {};
                preparedAccount.Account_Id = account.AccountId.Id;
                preparedAccount.Contact_Id = account.ContactID.Id;
                preparedAccount.CRId = account.CRId;
                //push row into array
                preparedAccounts.push(preparedAccount);
            });
            //assign array to @track accountsData variable
            this.accountsData = preparedAccounts;
        }
    }

More detail about flattening data

I want to use this data to delete custom object records. For this, I need to pass the data to the apex class. I do it as follows:

    deleteRelationship() {
        // Gets data of selected rows
        let selected = this.template.querySelector('lightning-datatable').getSelectedRows();
        //get data of all the selected rows of datatable
        // calling apex class method to delete the selected contact
        if (selected.length > 0) {
            del({ deleteIds: selected })
                .then(result => {
                    window.console.log('result ====> ' + result);
                })
                .catch(error => {
                    window.console.log('result ====> ' + error);
                });
        }

    }

How do I write the signature of the apex class to accept the data coming from JS file? I tried the following ways but they fail.

@AuraEnabled 
    public static void del(Map<String,String> deleteIds) {
    //gives null value for deleteIds
}

@AuraEnabled 
    public static void del(String[] deleteIds) {
    //gives error "Value provided is invalid for action parameter 'deleteIds' of type 'List'"
}

The data that I am trying to pass to apex function in not of a pirticular object. It's just flattened data. How do I pass it to apex? Please help. Thanks!

Update:

The data returned by getSelectedRows(). I just want to send CRId field value to the apex class and not the whole data.

Selected:[{"Contact_Role":"User Contact", "Account_Id":"0015400000Nmy5PAAR", "Contact_Id":"0035400000LHBGLAA5", "Account_Name":"Yahoo Inc Taiwan", "Account_MDM_Id":"10009899", "Is_Primary":false, "CRId":"a0854000002jBoRAAU"}]

Answer 1

You can loop over the "selected" list in javascript and get the CRId of all the accounts in a list and then you can pass that list as an argument to the apex method.

See the below example-

In js file:

    let ids = selected.map(selection => selection.CRId);

    // call apex method
    del({
         deleteIds : ids
    })

In apex file:

    public static void del(Id[] deleteIds) {
        System.debug('deleteIds'+deleteIds);
        //.. do what you want
    }