Calling Apex from LWC and Aura components

What the exam expects

• Read an LWC and its Apex method and decide whether the call must be wired or imperative, and what annotation the method needs.
• Spot parameter mistakes: a bare value instead of a parameter object, a missing $, or an undefined reactive value that stops the wire.
• Refresh wired Apex data correctly with refreshApex() and change provisioned data without mutating it.
• Fix an Aura client-side controller that never reaches the server, or whose attribute change made outside the framework never rerenders.
• Apply the @AuraEnabled rules for static methods, wrapper-class properties, unique action names and overloads.

Key terms: cacheable method (an @AuraEnabled(cacheable=true) method that only reads, required for @wire), reactive parameter (a $-prefixed wire parameter bound to a component property), wire-emitted value (the object the wire service provisions, which refreshApex() takes), server-side action (an Aura action created with component.get("c.method")), $A.getCallback() (the wrapper that brings code back into the Aura lifecycle).

The PD I basics (exposing methods, wire versus imperative in general, AuraHandledException) are in the Platform Developer guide's Apex for page components: controllers and wire adapters; this unit is the code-reading layer on top.

Key facts

Check yourself