Sf Lwc

# LWC Patterns Reference

## 1. Lightning Data Service (LDS) — Wire Adapters

### getRecord with Field Imports

```javascript
import { LightningElement, wire, api } from 'lwc';
import { getRecord, getFieldValue, getFieldDisplayValue } from 'lightning/uiRecordApi';
import NAME_FIELD from '@salesforce/schema/Account.Name';
import INDUSTRY_FIELD from '@salesforce/schema/Account.Industry';
import OWNER_NAME_FIELD from '@salesforce/schema/Account.Owner.Name';

const FIELDS = [NAME_FIELD, INDUSTRY_FIELD, OWNER_NAME_FIELD];

export default class AccountDetail extends LightningElement {
    @api recordId;

    @wire(getRecord, { recordId: '$recordId', fields: FIELDS })
    account;

    get name() {
        return getFieldValue(this.account.data, NAME_FIELD);
    }

    get industry() {
        return getFieldDisplayValue(this.account.data, INDUSTRY_FIELD);
    }

    get ownerName() {
        return getFieldValue(this.account.data, OWNER_NAME_FIELD);
    }

    get error() {
        return this.account.error;
    }
}
```

**Using optionalFields** (no error if field is inaccessible):

```javascript
@wire(getRecord, {
    recordId: '$recordId',
    fields: [NAME_FIELD],
    optionalFields: [OWNER_NAME_FIELD]
})
account;
```

### getObjectInfo for Object Metadata

```javascript
import { LightningElement, wire } from 'lwc';
import { getObjectInfo } from 'lightning/uiObjectInfoApi';
import ACCOUNT_OBJECT from '@salesforce/schema/Account';

export default class ObjectMetadata extends LightningElement {
    @wire(getObjectInfo, { objectApiName: ACCOUNT_OBJECT })
    objectInfo;

    get defaultRecordTypeId() {
        if (this.objectInfo.data) {
            return this.objectInfo.data.defaultRecordTypeId;
        }
        return null;
    }

    get fieldMap() {
        if (this.objectInfo.data) {
            return this.objectInfo.data.fields;
        }
        return {};
    }
}
```

### getPicklistValues and getPicklistValuesByRecordType

```javascript
import { LightningElement, wire, api } from 'lwc';
import { getObjectInfo } from 'lightning/uiObjectInfoApi';
import { getPicklistValues, getPicklistValuesByRecordType } from 'lightning/uiObjectInfoApi';
import ACCOUNT_OBJECT from '@salesforce/schema/Account';
import INDUSTRY_FIELD from '@salesforce/schema/Account.Industry';

export default class PicklistExample extends LightningElement {
    @api recordId;

    @wire(getObjectInfo, { objectApiName: ACCOUNT_OBJECT })
    objectInfo;

    // Single field picklist values
    @wire(getPicklistValues, {
        recordTypeId: '$objectInfo.data.defaultRecordTypeId',
        fieldApiName: INDUSTRY_FIELD
    })
    industryOptions;

    // All picklist values for a record type
    @wire(getPicklistValuesByRecordType, {
        objectApiName: ACCOUNT_OBJECT,
        recordTypeId: '$objectInfo.data.defaultRecordTypeId'
    })
    allPicklistValues;

    get industryPicklistValues() {
        if (this.industryOptions.data) {
            return this.industryOptions.data.values.map(item => ({
                label: item.label,
                value: item.value
            }));
        }
        return [];
    }
}
```

### refreshApex() Cache Invalidation

```javascript
import { LightningElement, wire, api } from 'lwc';
import { refreshApex } from '@salesforce/apex';
import getContacts from '@salesforce/apex/ContactController.getContacts';

export default class ContactList extends LightningElement {
    @api recordId;

    // Store the full wire result for refreshApex
    wiredContactsResult;

    @wire(getContacts, { accountId: '$recordId' })
    wiredContacts(result) {
        this.wiredContactsResult = result; // cache the provisioned value
        const { data, error } = result;
        if (data) {
            this.contacts = data;
            this.error = undefined;
        } else if (error) {
            this.error = error;
            this.contacts = [];
        }
    }

    async handleRefresh() {
        await refreshApex(this.wiredContactsRes