Salesforce Development

# Salesforce Development

Expert patterns for Salesforce platform development including Lightning Web
Components (LWC), Apex triggers and classes, REST/Bulk APIs, Connected Apps,
and Salesforce DX with scratch orgs and 2nd generation packages (2GP).

## Patterns

### Lightning Web Component with Wire Service

Use @wire decorator for reactive data binding with Lightning Data Service
or Apex methods. @wire fits LWC's reactive architecture and enables
Salesforce performance optimizations.

// myComponent.js
import { LightningElement, wire, api } from 'lwc';
import { getRecord, getFieldValue } from 'lightning/uiRecordApi';
import getRelatedRecords from '@salesforce/apex/MyController.getRelatedRecords';
import ACCOUNT_NAME from '@salesforce/schema/Account.Name';
import ACCOUNT_INDUSTRY from '@salesforce/schema/Account.Industry';

const FIELDS = [ACCOUNT_NAME, ACCOUNT_INDUSTRY];

export default class MyComponent extends LightningElement {
  @api recordId;  // Passed from parent or record page

  // Wire to Lightning Data Service (preferred for single records)
  @wire(getRecord, { recordId: '$recordId', fields: FIELDS })
  account;

  // Wire to Apex method (for complex queries)
  @wire(getRelatedRecords, { accountId: '$recordId' })
  wiredRecords({ error, data }) {
    if (data) {
      this.relatedRecords = data;
      this.error = undefined;
    } else if (error) {
      this.error = error;
      this.relatedRecords = undefined;
    }
  }

  get accountName() {
    return getFieldValue(this.account.data, ACCOUNT_NAME);
  }

  get isLoading() {
    return !this.account.data && !this.account.error;
  }

  // Reactive: changing recordId automatically re-fetches
}

// myComponent.html
<template>
  <lightning-card title={accountName}>
    <template if:true={isLoading}>
      <lightning-spinner alternative-text="Loading"></lightning-spinner>
    </template>

    <template if:true={account.data}>
      <p>Industry: {industry}</p>
    </template>

    <template if:true={error}>
      <p class="slds-text-color_error">{error.body.message}</p>
    </template>
  </lightning-card>
</template>

// MyController.cls
public with sharing class MyController {
  @AuraEnabled(cacheable=true)
  public static List<Contact> getRelatedRecords(Id accountId) {
    return [
      SELECT Id, Name, Email, Phone
      FROM Contact
      WHERE AccountId = :accountId
      WITH SECURITY_ENFORCED
      LIMIT 100
    ];
  }
}

### Context

- building LWC components
- fetching Salesforce data
- reactive UI

### Bulkified Apex Trigger with Handler Pattern

Apex triggers must be bulkified to handle 200+ records per transaction.
Use handler pattern for separation of concerns, testability, and
recursion prevention.

// AccountTrigger.trigger
trigger AccountTrigger on Account (
  before insert, before update, before delete,
  after insert, after update, after delete, after undelete
) {
  new AccountTriggerHandler().run();
}

// TriggerHandler.cls (base class)
public virtual class TriggerHandler {
  // Recursion prevention
  private static Set<String> executedHandlers = new Set<String>();

  public void run() {
    String handlerName = String.valueOf(this).split(':')[0];

    // Prevent recursion
    String contextKey = handlerName + '_' + Trigger.operationType;
    if (executedHandlers.contains(contextKey)) {
      return;
    }
    executedHandlers.add(contextKey);

    switch on Trigger.operationType {
      when BEFORE_INSERT { this.beforeInsert(); }
      when BEFORE_UPDATE { this.beforeUpdate(); }
      when BEFORE_DELETE { this.beforeDelete(); }
      when AFTER_INSERT { this.afterInsert(); }
      when AFTER_UP