@wire vs. Imperative Apex in Lightning Web Components (LWC) ⚡

When working with Apex in LWC, choosing the right data fetching method is crucial for building scalable, efficient, and high-performing components. The two primary approaches are:

1️⃣ @wire (Reactive & Automatic)
2️⃣ Imperative Apex (Manual & Flexible)

Let’s break them down in detail, including use cases, examples, advantages, and best practices.

🔹 1. @wire – Reactive & Automatic

The @wire decorator is a reactive and declarative approach to fetching data from Apex in LWC. It automatically retrieves data and updates the component whenever the underlying data changes in Salesforce.

✅ Key Features of @wire:

✔ Fetches data automatically when the component loads.
✔ Supports caching for better performance.
✔ Automatically updates when data changes in Salesforce.
✔ Works well with read-only data that doesn’t require manual refresh.

🛠 Example of @wire:

Apex Controller (Apex Class)

public with sharing class AccountController {
    @AuraEnabled(cacheable=true)
    public static List<Account> getAccounts() {
        return [SELECT Id, Name, Industry FROM Account LIMIT 10];
    }
}

🔹 cacheable=true: Enables Salesforce to cache results and automatically refresh them when necessary, improving performance.

LWC Component (JavaScript – JS File)

import { LightningElement, wire } from 'lwc';
import getAccounts from '@salesforce/apex/AccountController.getAccounts';

export default class AccountList extends LightningElement {
    @wire(getAccounts) accounts;
}

LWC Component (HTML File)

<template>
    <lightning-card title="Account List">
        <template if:true={accounts.data}>
            <template for:each={accounts.data} for:item="acc">
                <p key={acc.Id}>{acc.Name} - {acc.Industry}</p>
            </template>
        </template>
        <template if:true={accounts.error}>
            <p>Error fetching accounts</p>
        </template>
    </lightning-card>
</template>

⚡ How This Works:

✅ The getAccounts() Apex method runs automatically when the component loads.
✅ If the account records change in Salesforce, the data updates automatically in the component.
✅ Salesforce caches the data for better performance.

🛠 When to Use @wire?

✔ Read-only or frequently changing data (e.g., account lists, case statuses).
✔ Performance-optimized applications where caching improves speed.
✔ Automatic reactivity when record changes occur in the database.

🔹 2. Imperative Apex – Manual & Flexible

Imperative Apex allows you to manually call Apex methods within JavaScript, providing greater control over when and how data is retrieved.

✅ Key Features of Imperative Apex:

✔ Fetches data only when explicitly triggered (e.g., button click, user input).
✔ Provides full control over when and how Apex is executed.
✔ Useful when actions depend on user interaction or custom business logic.

🛠 Example of Imperative Apex:

Apex Controller (Apex Class)

(Same Apex class used in @wire example)

LWC Component (JavaScript – JS File)

import { LightningElement, track } from 'lwc';
import getAccounts from '@salesforce/apex/AccountController.getAccounts';

export default class AccountListImperative extends LightningElement {
    @track accounts;
    @track error;

    handleLoadAccounts() {
        getAccounts()
            .then(result => {
                this.accounts = result;
                this.error = undefined;
            })
            .catch(error => {
                this.error = error;
                this.accounts = undefined;
            });
    }
}

LWC Component (HTML File)

<template>
    <lightning-card title="Account List">
        <lightning-button label="Load Accounts" onclick={handleLoadAccounts}></lightning-button>
        
        <template if:true={accounts}>
            <template for:each={accounts} for:item="acc">
                <p key={acc.Id}>{acc.Name} - {acc.Industry}</p>
            </template>
        </template>

        <template if:true={error}>
            <p>Error fetching accounts</p>
        </template>
    </lightning-card>
</template>

⚡ How This Works:

✅ The Apex method runs only when the button is clicked, not automatically.
✅ The result is manually stored in the accounts variable for rendering.
✅ Errors are handled manually in the catch block.

🛠 When to Use Imperative Apex?

✔ When you need manual control over when the Apex method is called.
✔ When Apex calls depend on user interaction (e.g., button click, form submission).
✔ When you need to modify or process data before displaying it.

🚀 Key Differences: @wire vs. Imperative Apex

Feature	@wire	Imperative Apex
Execution Type	Reactive (Automatic)	Manual (User-triggered)
Best for	Read-only, frequently updated data	User-driven actions (button clicks, form submissions)
Caching	Yes, when `cacheable=true` is used	No caching by default
Flexibility	Less flexible	More flexible
When to Use?	Auto-refreshing, real-time updates	When explicit control over data fetching is needed

🎯 Best Practices for Using @wire and Imperative Apex

✅ Use @wire whenever possible for optimized performance and automatic updates.
✅ Use Imperative Apex only when you need manual control or user-triggered actions.
✅ Handle errors properly using try-catch blocks or displaying meaningful error messages.
✅ Avoid calling Apex in loops to prevent governor limits.

🚀 Final Thoughts

Both @wire and Imperative Apex are essential tools for fetching and managing data in LWC. Choosing the right approach depends on your use case, performance needs, and flexibility requirements.

✔ @wire: Best for real-time, reactive updates.
✔ Imperative Apex: Best for user-driven actions.

💡 Which approach do you use more often? Let’s discuss in the comments! 👇

#Salesforce #LWC #WireVsImperative #LightningWebComponents #Apex #CodingBestPractices 🚀

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