Inline Editing in lightning-datatable in Salesforce Lightning Web Component(lwc)

 This post explains, inline editing in lightning-datatable in salesforce lightning web components(lwc).

HTML Code:

<template>
    <lightning-card title="Inline Edit With Lightning Datatable in LWC">
        <template if:true={contacts.data}>
            <lightning-datatable key-field="Id" 
                                 data={contacts.data} 
                                 columns={columns} 
                                 onsave={handleSave}
                                 draft-values={saveDraftValues} 
                                 hide-checkbox-column 
                                 show-row-number-column>
            </lightning-datatable>
        </template>
    </lightning-card>
</template>

Javascript Code:

import { LightningElement, wire, track } from 'lwc';
import getContacts from '@salesforce/apex/LWCExampleController.getContacts';
import { updateRecord } from 'lightning/uiRecordApi';
import { ShowToastEvent } from 'lightning/platformShowToastEvent';
import { refreshApex } from '@salesforce/apex';
// datatable columns
const columns = [
    {
        label: 'Name',
        fieldName: 'Name',
        type: 'text',
    }, {
        label: 'FirstName',
        fieldName: 'FirstName',
        type: 'text',
        editable: true,
    }, {
        label: 'LastName',
        fieldName: 'LastName',
        type: 'text',
        editable: true,
    }, {
        label: 'Phone',
        fieldName: 'Phone',
        type: 'phone',
        editable: true
    }
];

export default class InlineEditTable extends LightningElement {

    columns = columns;
    @track contacts;
    saveDraftValues = [];

    @wire(getContacts)
    cons(result) {
        this.contacts = result;
        if (result.error) {
            this.contacts = undefined;
        }
    };

    handleSave(event) {
        this.saveDraftValues = event.detail.draftValues;
        const recordInputs = this.saveDraftValues.slice().map(draft => {
            const fields = Object.assign({}, draft);
            return { fields };
        });

        // Updateing the records using the UiRecordAPi
        const promises = recordInputs.map(recordInput => updateRecord(recordInput));
        Promise.all(promises).then(res => {
            this.dispatchEvent(
                new ShowToastEvent({
                    title: 'Success',
                    message: 'Records Updated Successfully!!',
                    variant: 'success'
                })
            );
            this.saveDraftValues = [];
            return this.refresh();
        }).catch(error => {
            this.dispatchEvent(
                new ShowToastEvent({
                    title: 'Error',
                    message: 'An Error Occured!!',
                    variant: 'error'
                })
            );
        }).finally(() => {
            this.saveDraftValues = [];
        });
    }

    // This function is used to refresh the table once data updated
    async refresh() {
        await refreshApex(this.contacts);
    }
}

Apex Code:

public inherited sharing class LWCExampleController {

    @AuraEnabled(Cacheable = true)
    public static List<Contact> getContacts() {
        return [SELECT Id, Name, FirstName, LastName, Phone, Email 
                FROM Contact 
                WHERE Email != null 
                AND Phone != null 
                ORDER BY CreatedDate DESC NULLS LAST limit 10];
    }
}

Output: