This below code sample shows
how to detect the SharePoint current running environment using typescript. The SharePoint Framework (SPFx) is a page and web part model that
provides full support for client-side SharePoint development, easy integration
with SharePoint data and support for open source tooling. Import
this below namespace in your solution

Source:https://rencore.com/wp/wp-content/uploads/2018/03/framework-1.png
import { Environment, EnvironmentType } from '@microsoft/sp-core-library'; Include this below snippet in your Source code TS file if(Environment.type == EnvironmentType.ClassicSharePoint){ //do some stuff on classic page }else if(Environment.type === EnvironmentType.SharePoint){ //do some stuff on modern page }else if(Environment.type === EnvironmentType.Local){ //do some stuff on SharePoint workbench page }