After adding new fields to an Apex query, an existing LWC stopped working. The component compiled successfully, but users now see errors or missing data. The changes seemed minor, so the failure was unexpected. I want to understand why this happens.
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After adding new fields to an Apex query, an existing LWC stopped working. The component compiled successfully, but users now see errors or missing data. The changes seemed minor, so the failure was unexpected. I want to understand why this happens.
LWCs rely on the exact shape of the data returned by Apex. Adding fields can change serialization size, field-level security behavior, or introduce null values that weren’t handled previously. Any of these can break client-side assumptions.
Another common issue is that new fields may not be accessible to all users. When Apex runs with sharing, missing access can cause parts of the response to be empty or inconsistent.
The fix is usually adding null checks, validating permissions, and avoiding returning unnecessary fields.
Takeaway: Even small Apex changes can impact LWCs if assumptions aren’t updated.