How to get Salesforce Base URL in Lightning Web Component

To get Salesforce base URL use the window.location object can be used to get the current page address (URL).
The window.location.origin property returns the origin URL of the current page.

baseURL.html:

<template>
    <lightning-card title="Salesforce Base URL in Lighting Web Component">
        <div class="slds-text-heading_medium slds-text-align-center">
            SFDC Base URL : <p></p><lightning-formatted-url value={sfdcBaseURL} ></lightning-formatted-url></p>
        </div>
    </lightning-card>

</template>

baseURL.js:

import { LightningElement } from 'lwc';
export default class BaseURL extends LightningElement {
    sfdcBaseURL;
    renderedCallback() {
        this.sfdcBaseURL = window.location.origin;
    }

}
baseURL.js-meta.xml:

<?xml version="1.0" encoding="UTF-8"?>
<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
    <apiVersion>48.0</apiVersion>
    <isExposed>true</isExposed>
    <targets>
        <target>lightning__AppPage</target>
        <target>lightning__RecordPage</target>
        <target>lightning__HomePage</target>
    </targets>

</LightningComponentBundle>

Output: