// WITH USER_MODE — throws FieldAccessException for restricted fields List<Account> accs = [SELECT Id, Name, Salary__c, Revenue__c FROM Account WITH USER_MODE]; // User 2 without FLS on Salary__c → FieldAccessException! // System mode — returns all 4 fields for ALL users (bypasses FLS) public without sharing class QueryClass { public static List<Account> getAccounts() { return [SELECT Id, Name, Salary__c, Revenue__c FROM Account]; } } // Safe approach — check FLS before querying if(Schema.SObjectType.Account.fields.Salary__c.isAccessible()) { // include Salary__c in query }

// Use allOrNone=false — partial success instead of full rollback public void execute(Database.BatchableContext bc, List<Account> scope) { List<Database.SaveResult> results = Database.update(scope, false); for(Database.SaveResult sr : results) { if(!sr.isSuccess()) { // Log failed records — don't throw exception failedIds.add(sr.getId()); // failedIds in Database.Stateful for(Database.Error err : sr.getErrors()) { System.debug('Error: ' + err.getMessage()); } } } } // finish() — re-process or notify about failures public void finish(Database.BatchableContext bc) { if(!failedIds.isEmpty()) { // Launch another batch for failed records only Database.executeBatch(new RetryBatch(failedIds), 50); } }

// Shared utility module — utils/utils.js (no HTML file needed) const formatCurrency = (amount, currency = 'INR') => { return new Intl.NumberFormat('en-IN', { style: 'currency', currency }).format(amount); }; const validateEmail = (email) => { return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email); }; export { formatCurrency, validateEmail }; // In any LWC component — import and use // import { formatCurrency, validateEmail } from 'c/utils'; // this.formattedAmount = formatCurrency(this.amount);

// HTML template // <lightning-input label="Name" value={name} onchange={handleName}></lightning-input> // <lightning-input label="Phone" value={phone} onchange={handlePhone}></lightning-input> // <lightning-button label="Update" onclick={handleUpdate}></lightning-button> // JavaScript import { LightningElement, api, wire, track } from 'lwc'; import { getRecord } from '@salesforce/uiRecordApi'; import updateRecord from '@salesforce/apex/AccountController.updateRecord'; import { ShowToastEvent } from 'lightning/platformShowToastEvent'; export default class UpdateForm extends LightningElement { @api recordId; @track name; @track phone; handleName(e) { this.name = e.target.value; } handlePhone(e) { this.phone = e.target.value; } handleUpdate() { updateRecord({ recordId: this.recordId, name: this.name, phone: this.phone }) .then(() => { this.dispatchEvent(new ShowToastEvent({ title: 'Success', message: 'Updated!', variant: 'success' })); }) .catch(error => console.error(error)); } }

// Automatic from Lightning Record Page import { LightningElement, api } from 'lwc'; export default class MyComponent extends LightningElement { @api recordId; // Salesforce passes this automatically on record pages @api objectApiName; // Also available automatically } // Or from CurrentPageReference import { CurrentPageReference } from 'lightning/navigation'; import { wire } from 'lwc'; @wire(CurrentPageReference) pageRef; // this.pageRef.state.recordId — for community or custom pages

trigger AccountTrigger on Account (after insert, after update) { Set<Id> ids = new Set<Id>(); for(Account a : Trigger.new) ids.add(a.Id); // Call @future — pass Set of Ids (primitive collection) AccountHelper.processAsync(ids); } public class AccountHelper { @future public static void processAsync(Set<Id> accountIds) { // Runs in separate transaction — fresh governor limits List<Account> accounts = [SELECT Id, Name FROM Account WHERE Id IN :accountIds]; // Process accounts... } }

// Apex class with @InvocableMethod public class FlowAccountUpdater { @InvocableMethod(label='Update Account Industry' description='Updates industry field') public static List<String> updateIndustry(List<FlowInput> inputs) { List<String> results = new List<String>(); for(FlowInput input : inputs) { // Process input.accountId and input.industry results.add('Updated: ' + input.accountId); } return results; } public class FlowInput { @InvocableVariable(required=true) public Id accountId; @InvocableVariable public String industry; } }

@isTest static void testFutureMethod() { // Setup test data BEFORE startTest Account a = new Account(Name = 'Test'); insert a; Test.startTest(); // Fresh governor limits from here // Call the code that triggers @future AccountHelper.processAsync(new Set<Id>{a.Id}); Test.stopTest(); // @future executes HERE before moving to assertions // Assert AFTER stopTest — @future has completed Account updated = [SELECT Id, Description FROM Account WHERE Id = :a.Id]; System.assertNotEquals(null, updated.Description); }

trigger ChildTrigger on Child__c (after insert, after update, after delete, after undelete) { Set<Id> accountIds = new Set<Id>(); List<Child__c> records = Trigger.isDelete ? Trigger.old : Trigger.new; for(Child__c c : records) { if(c.Account__c != null) accountIds.add(c.Account__c); } // Aggregate sum of Amount__c per Account List<AggregateResult> totals = [ SELECT Account__c, SUM(Amount__c) total FROM Child__c WHERE Account__c IN :accountIds GROUP BY Account__c ]; Map<Id, Decimal> sumMap = new Map<Id, Decimal>(); for(AggregateResult ar : totals) { sumMap.put((Id) ar.get('Account__c'), (Decimal) ar.get('total')); } List<Account> toUpdate = new List<Account>(); for(Id accId : accountIds) { toUpdate.add(new Account( Id = accId, Total_Amount__c = sumMap.containsKey(accId) ? sumMap.get(accId) : 0 )); } if(!toUpdate.isEmpty()) update toUpdate; }

// meta XML — add FlowScreen target // <targets><target>lightning__FlowScreen</target></targets> // <targetConfigs> // <targetConfig targets="lightning__FlowScreen"> // <property name="inputValue" type="String" /> // <property name="outputValue" type="String" role="outputOnly" /> // </targetConfig> // </targetConfigs> // JavaScript — receive input, send output back to Flow import { FlowAttributeChangeEvent } from 'lightning/flowSupport'; @api inputValue; // Flow passes value in @api outputValue; // Flow reads value out handleChange(event) { this.outputValue = event.target.value; // Notify Flow of the changed value this.dispatchEvent(new FlowAttributeChangeEvent('outputValue', this.outputValue)); }

// Child component — expose method with @api import { LightningElement, api } from 'lwc'; export default class ChildComponent extends LightningElement { @api doSomething(value) { console.log('Child received: ' + value); // Do work } } // Parent component — call child method // <c-child-component></c-child-component> // <lightning-button label="Call Child" onclick={callChild}></lightning-button> import { LightningElement } from 'lwc'; export default class ParentComponent extends LightningElement { callChild() { const child = this.template.querySelector('c-child-component'); child.doSomething('Hello from parent'); } }

// Load all FAQs once @wire(getFAQs) wiredFAQs({ data, error }) { if(data) { this.allFAQs = data; this.filteredFAQs = data; // show all initially } } // Filter client-side as user types — no Apex call per keystroke handleSearch(event) { const searchTerm = event.target.value.toLowerCase(); this.filteredFAQs = this.allFAQs.filter(faq => faq.Question__c.toLowerCase().includes(searchTerm) || faq.Answer__c.toLowerCase().includes(searchTerm) ); }

// CAUSES Mixed DML Error Account a = new Account(Name = 'Test'); insert a; // Non-setup DML PermissionSetAssignment psa = new PermissionSetAssignment( AssigneeId = userId, PermissionSetId = psId); insert psa; // Setup DML → MIXED DML ERROR! // FIX — separate setup DML into @future @future public static void assignPermSet(Id userId, Id psId) { PermissionSetAssignment psa = new PermissionSetAssignment( AssigneeId = userId, PermissionSetId = psId); insert psa; // New transaction — no conflict } // In test class — use System.runAs() to avoid Mixed DML System.runAs(new User(Id = UserInfo.getUserId())) { insert psa; // runAs creates separate context }

// Recursion prevention with static Boolean public class TriggerHelper { public static Boolean hasRun = false; } trigger AccountTrigger on Account (after update) { if(!TriggerHelper.hasRun) { TriggerHelper.hasRun = true; // Set before DML List<Account> toUpdate = new List<Account>(); for(Account a : Trigger.new) { toUpdate.add(new Account(Id=a.Id, Description='Updated')); } update toUpdate; // This fires trigger again — but hasRun is true, so it exits } }

trigger CaseTrigger on Case (after insert) { List<Case> toUpdate = new List<Case>(); for(Case c : Trigger.new) { if(c.SuppliedEmail != null && c.ContactId == null) { List<Contact> existing = [SELECT Id FROM Contact WHERE Email = :c.SuppliedEmail LIMIT 1]; if(!existing.isEmpty()) { toUpdate.add(new Case(Id = c.Id, ContactId = existing[0].Id)); } else { // Create new Contact Contact newCon = new Contact( LastName = c.SuppliedName != null ? c.SuppliedName : 'Unknown', Email = c.SuppliedEmail ); insert newCon; toUpdate.add(new Case(Id = c.Id, ContactId = newCon.Id)); } } } if(!toUpdate.isEmpty()) update toUpdate; }

// Apex Managed Sharing — create share record programmatically public static void shareRecord(Id recordId, Id userId, String accessLevel) { Account__Share share = new Account__Share(); share.AccountId = recordId; // Record to share share.UserOrGroupId = userId; // User or Group to share with share.AccountAccessLevel = accessLevel; // 'Read' or 'Edit' share.RowCause = Schema.Account__Share.RowCause.Manual; Database.SaveResult result = Database.insert(share, false); if(!result.isSuccess()) { System.debug('Share error: ' + result.getErrors()); } } // Custom RowCause for Apex Managed Sharing // Create custom Sharing Reason on the object first // share.RowCause = Schema.MyObject__Share.RowCause.MyCustomReason__c;

public class AccountBatch implements Database.Batchable<sObject> { public Database.QueryLocator start(Database.BatchableContext bc) { return Database.getQueryLocator('SELECT Id, Name FROM Account'); // Supports 50 million records } public void execute(Database.BatchableContext bc, List<Account> scope) { // Fresh governor limits per chunk // DO NOT call executeBatch() here — nesting batches is not allowed for(Account a : scope) { a.Description = 'Processed'; } update scope; } public void finish(Database.BatchableContext bc) { // CAN chain another batch from finish() Database.executeBatch(new ContactBatch(), 200); } }

// Standard — Child-to-Parent (dot notation) [SELECT Name, Account.Name, Account.Industry FROM Contact] [SELECT Name, Owner.Name, Owner.Profile.Name FROM Account] // Standard — Parent-to-Child (subquery, plural) [SELECT Name, (SELECT Name FROM Contacts) FROM Account] [SELECT Name, (SELECT Name FROM Opportunities) FROM Account] // Custom — lookup field: Territory__c → relationship: Territory__r [SELECT Name, Territory__r.Name FROM Account__c] // Custom — Parent-to-Child: relationship name on child + __r plural [SELECT Name, (SELECT Name FROM Accounts__r) FROM Territory__c] // How to find relationship name: Object Manager → Field → Relationship Name

trigger AccountTrigger on Account (before insert, after insert) { // Same Trigger.new available in both contexts if(Trigger.isBefore && Trigger.isInsert) { for(Account a : Trigger.new) { // Modify field directly — NO DML needed, saves extra query a.Description = 'Set in before insert'; } } if(Trigger.isAfter && Trigger.isInsert) { // Id is now available — use for related record operations for(Account a : Trigger.new) { System.debug('Account Id: ' + a.Id); } } }

/* Styles in child component CSS — scoped, don't leak out */ p { color: red; } /* Only affects <p> tags inside THIS component */ /* Parent CANNOT style child component internals */ /* c-child p { color: blue; } → WON'T WORK in parent CSS */ /* To style across shadow boundary — use CSS custom properties */ /* Child exposes: --text-color: var(--text-color, black); */ /* Parent sets: c-child { --text-color: blue; } */

public Object startRequest() { Continuation con = new Continuation(60); // 60 second timeout con.continuationMethod = 'processResponse'; HttpRequest req = new HttpRequest(); req.setEndpoint('https://slow-api.example.com/data'); req.setMethod('GET'); this.requestId = con.addHttpRequest(req); return con; // Hand control back to Salesforce } public Object processResponse() { HttpResponse res = Continuation.getResponse(this.requestId); // Process response return Page.myPage; }

// Publisher component import { publish, MessageContext } from 'lightning/messageService'; import MY_CHANNEL from '@salesforce/messageChannel/MyChannel__c'; @wire(MessageContext) messageContext; sendMessage() { publish(this.messageContext, MY_CHANNEL, { payload: 'Hello sibling!' }); } // Subscriber component import { subscribe, MessageContext } from 'lightning/messageService'; import MY_CHANNEL from '@salesforce/messageChannel/MyChannel__c'; @wire(MessageContext) messageContext; connectedCallback() { this.subscription = subscribe(this.messageContext, MY_CHANNEL, (msg) => { this.receivedMessage = msg.payload; }); }

// Child component HTML — defines slot placeholders <template> <div class="header"> <slot name="header">Default Header</slot> </div> <div class="body"> <slot></slot> <!-- Default (unnamed) slot --> </div> </template> // Parent component — fills the slots <c-child> <span slot="header">My Custom Header</span> <p>This goes into the default slot</p> </c-child>

// WITHOUT Named Credential — credentials in code (bad practice!) HttpRequest req = new HttpRequest(); req.setEndpoint('https://api.example.com/data'); req.setHeader('Authorization', 'Bearer hardcoded_token'); // NEVER do this! // WITH Named Credential — credentials in Setup, secure HttpRequest req = new HttpRequest(); req.setEndpoint('callout:MyNamedCredential/endpoint'); // Named Credential name req.setMethod('GET'); // Auth header added automatically by Salesforce! Http h = new Http(); HttpResponse res = h.send(req);

@isTest private class AccountBatchTest { @isTest static void testBatch() { // Create test data List<Account> accounts = new List<Account>(); for(Integer i = 0; i < 200; i++) { accounts.add(new Account(Name = 'Test ' + i)); } insert accounts; Test.startTest(); AccountBatch batch = new AccountBatch(); Database.executeBatch(batch, 200); // Runs synchronously in test Test.stopTest(); // Batch completes here // Assert after stopTest List<Account> updated = [SELECT Id, Description FROM Account]; System.assertEquals('Processed', updated[0].Description); } }

public class Step1Queueable implements Queueable { public void execute(QueueableContext ctx) { // Do Step 1 work List<Account> accounts = [SELECT Id FROM Account LIMIT 200]; for(Account a : accounts) a.Description = 'Step 1'; update accounts; // Chain Step 2 — only 1 enqueue per execute() allowed System.enqueueJob(new Step2Queueable()); } } public class Step2Queueable implements Queueable { public void execute(QueueableContext ctx) { // Step 2 runs after Step 1 completes } }

// Mock class @isTest public class MockCallout implements HttpCalloutMock { public HTTPResponse respond(HTTPRequest req) { HttpResponse res = new HttpResponse(); res.setStatusCode(200); res.setBody('{"success": true, "data": "test"}'); return res; } } // Test class using mock @isTest static void testCallout() { Test.setMock(HttpCalloutMock.class, new MockCallout()); Test.startTest(); MyCalloutClass.makeCallout(); // Mock intercepts the callout Test.stopTest(); // Assert based on mock response }

// meta XML — expose for list view action <targets> <target>lightning__ListView</target> </targets> <targetConfigs> <targetConfig targets="lightning__ListView"> <property name="selectedRecordIds" type="String[]" /> </targetConfig> </targetConfigs> // JavaScript — receive selected record Ids @api selectedRecordIds; // Array of selected record Ids from list view connectedCallback() { console.log('Selected: ', this.selectedRecordIds); // Process selected records }

import { LightningElement } from 'lwc'; import { loadScript, loadStyle } from 'lightning/platformResourceLoader'; import CHART_JS from '@salesforce/resourceUrl/ChartJS'; export default class MyChart extends LightningElement { connectedCallback() { loadScript(this, CHART_JS) .then(() => { // ChartJS now available — initialize chart const ctx = this.template.querySelector('canvas'); new Chart(ctx, { type: 'bar', data: {} }); }) .catch(error => console.error(error)); } }

// Parent → Child (via @api property) // Parent HTML: <c-child message={parentMessage}></c-child> // Child JS receives it @api message; // Parent sets this as attribute // Child → Parent (via Custom Event) // Child fires event handleClick() { this.dispatchEvent(new CustomEvent('childaction', { detail: { value: 'data from child' } })); } // Parent listens // <c-child onchildaction={handleChildAction}></c-child> handleChildAction(event) { this.receivedData = event.detail.value; }

// Query job status List<AsyncApexJob> jobs = [ SELECT Id, Status, ExtendedStatus, NumberOfErrors, JobItemsProcessed, TotalJobItems, CreatedDate FROM AsyncApexJob WHERE ApexClass.Name = 'MyBatchClass' ORDER BY CreatedDate DESC LIMIT 5 ]; // Common failure causes: // 1. ExtendedStatus shows the exception // 2. Governor limits hit in execute() // 3. Null pointer exception in start() query // 4. Schedule aborted by another admin // 5. Org maintenance window killed running jobs

// Option 1 — Custom field bypass // Add checkbox field: Bypass_Validation__c on the object // Validation rule condition: // AND(NOT(Bypass_Validation__c), ISBLANK(Required_Field__c)) // Set Bypass_Validation__c = true via Flow/Apex for specific scenarios // Option 2 — Custom Permission bypass (better for profile-based bypass) // Create Custom Permission: Bypass_Validation_Rules // Assign to specific Profile or Permission Set // Validation rule condition: // AND(NOT($Permission.Bypass_Validation_Rules), ISBLANK(Required_Field__c))

// Option 1 — Check by User Profile name trigger AccountTrigger on Account (before insert) { User currentUser = [SELECT Profile.Name FROM User WHERE Id = :UserInfo.getUserId()]; if(currentUser.Profile.Name == 'Integration User Profile') { return; // Skip all logic for integration user } // Normal trigger logic } // Option 2 — Custom Permission (better practice) if(FeatureManagement.checkPermission('Bypass_Account_Trigger')) { return; // Integration user has this permission, skip trigger }