currentLocation.html

<template>
  <div class="slds-grid slds-wrap">
    <div class="slds-col slds-size_1-of-1 slds-medium-size_12-of-12 slds-large-size_12-of-12 slds-align_absolute-center">
      <button class="slds-button slds-button_brand" onclick={handleCurrentLocation}>Get my current
      location</button>
    </div>
  </div>
</template>

currentLocation.js

export default class CurrentLocation extends LightningElement {
  handleCurrentLocation() {
        navigator.geolocation.getCurrentPosition(success => {
            this.showSpinner = true;
            this.lat = success.coords.latitude;
            this.long = success.coords.longitude;
            console.log('lat -> ' + this.lat);
            console.log('long -> ' + this.long);
  }
}