Check you are on which page from LWC

To check if the Lightning component is in Lightning Community Page or in Salesforce Lightning CRM page, we can make use of Site Class‘s method – getSiteType().

this return these values

Create an @AuraEnabled method in Apex Controller:

@AuraEnabled
public static String getSiteType() {
    return Site.getSiteType();

controller to fetch

var communityPageKeys = ['ChatterNetwork', 'ChatterNetworkPicasso'];
var action = component.get("c.getSiteType");

action.setCallback(this, function (response) {
    if (response.getState() === "SUCCESS") {
        if (communityPageKeys.indexOf(response.getReturnValue()) < 0) {
            // This is not a community page
        } else {
            // This is a community page
        }
    }
});

$A.enqueueAction(action);

Reference [https://vijayasankarn.wordpress.com/2018/02/12/lightning-component-is-it-in-community-or-in-lightning-page/]