LWC counterpart to Aura's force:createRecord event

In the new salesforce release Spring'20, we have this privilege to set the predefined values. We can now make the field API names and their values as a string and pass it to pageReference.state.defaultFieldValues attribute on standard__objectPage page reference types.

You can have the look here - https://releasenotes.docs.salesforce.com/en-us/spring20/release-notes/rn_lc_navigate_to_record_dfv.htm

For instance -

import { LightningElement } from 'lwc';
import { NavigationMixin } from 'lightning/navigation';

export default class Demo extends NavigationMixin(LightningElement) {

    handleClick(){
        let temp = {
            type: 'standard__objectPage',
            attributes: {
                objectApiName: 'Account',
                actionName: 'new'                
            },
            state : {
                nooverride: '1',
                defaultFieldValues:"Name=Salesforce,AccountNumber=A1,AnnualRevenue=37000,Phone=7055617159"
            }
        };
        this[NavigationMixin.Navigate](temp);
    }

}

Note - Spring'20 is only available for sandboxes for now.

To construct a custom button or link that launches a new record with prepopulated field values, use this sample formula:

/lightning/o/Account/new?defaultFieldValues=
    Name={!URLENCODE(Account.Name)},
    OwnerId={!Account.OwnerId},
    AccountNumber={!Account.AccountNumber},
    NumberOfEmployees=35000,
    CustomCheckbox__c={!IF(Account.SomeCheckbox__c, true, false)}

Release Notes: https://releasenotes.docs.salesforce.com/en-us/spring20/release-notes/rn_general_lex_navigate_to_record_dfv.htm