Error Handling and Refreshing Apex-Backed Data

@AuraEnabled
public static void createOrder(String accountId) {
    if (String.isBlank(accountId)) {
        throw new AuraHandledException('An Account is required to create an Order.');
    }
    // ... create the order
}

By default, Salesforce strips the details off most exceptions before they reach the client, for security — a plain DmlException's real message never reaches JavaScript. AuraHandledException is the deliberate exception built for this exact purpose: its message is preserved and passed through to the component.

try {
    await createOrder({ accountId: this.selectedAccountId });
} catch (error) {
    this.errorMessage = error.body?.message ?? 'An unexpected error occurred.';
}

For an imperative call, wrap it in try/catch as usual. For a @wire-based read, the wired result carries an error property directly (this.wiredResult.error) rather than throwing.

import { refreshApex } from '@salesforce/apex';

async handleSave() {
    await updateOpportunityStage({ opportunityId: this.recordId, stage: 'Closed Won' });
    await refreshApex(this.wiredOpportunities);
}

The same refreshApex pattern from Module 6, Lesson 5 applies directly here — after a write via an imperative Apex call, a wired Apex read won't automatically know to re-fetch, so refreshApex forces it to pick up the change.