Removing Markers

// In the following example, markers appear when the user clicks on the map.
// The markers are stored in an array.
// The user can then click an option to hide, show or delete the markers.
let map: google.maps.Map;
let markers: google.maps.Marker[] = [];

function initMap(): void {
  const haightAshbury = { lat: 37.769, lng: -122.446 };

  map = new google.maps.Map(document.getElementById("map") as HTMLElement, {
    zoom: 12,
    center: haightAshbury,
    mapTypeId: "terrain",
  });

  // This event listener will call addMarker() when the map is clicked.
  map.addListener("click", (event: google.maps.MapMouseEvent) => {
    addMarker(event.latLng!);
  });

  // add event listeners for the buttons
  document
    .getElementById("show-markers")!
    .addEventListener("click", showMarkers);
  document
    .getElementById("hide-markers")!
    .addEventListener("click", hideMarkers);
  document
    .getElementById("delete-markers")!
    .addEventListener("click", deleteMarkers);

  // Adds a marker at the center of the map.
  addMarker(haightAshbury);
}

// Adds a marker to the map and push to the array.
function addMarker(position: google.maps.LatLng | google.maps.LatLngLiteral) {
  const marker = new google.maps.Marker({
    position,
    map,
  });

  markers.push(marker);
}

// Sets the map on all markers in the array.
function setMapOnAll(map: google.maps.Map | null) {
  for (let i = 0; i < markers.length; i++) {
    markers[i].setMap(map);
  }
}

// Removes the markers from the map, but keeps them in the array.
function hideMarkers(): void {
  setMapOnAll(null);
}

// Shows any markers currently in the array.
function showMarkers(): void {
  setMapOnAll(map);
}

// Deletes all markers in the array by removing references to them.
function deleteMarkers(): void {
  hideMarkers();
  markers = [];
}

declare global {
  interface Window {
    initMap: () => void;
  }
}
window.initMap = initMap;
index.ts

// In the following example, markers appear when the user clicks on the map.
// The markers are stored in an array.
// The user can then click an option to hide, show or delete the markers.
let map;
let markers = [];

function initMap() {
  const haightAshbury = { lat: 37.769, lng: -122.446 };

  map = new google.maps.Map(document.getElementById("map"), {
    zoom: 12,
    center: haightAshbury,
    mapTypeId: "terrain",
  });
  // This event listener will call addMarker() when the map is clicked.
  map.addListener("click", (event) => {
    addMarker(event.latLng);
  });
  // add event listeners for the buttons
  document
    .getElementById("show-markers")
    .addEventListener("click", showMarkers);
  document
    .getElementById("hide-markers")
    .addEventListener("click", hideMarkers);
  document
    .getElementById("delete-markers")
    .addEventListener("click", deleteMarkers);
  // Adds a marker at the center of the map.
  addMarker(haightAshbury);
}

// Adds a marker to the map and push to the array.
function addMarker(position) {
  const marker = new google.maps.Marker({
    position,
    map,
  });

  markers.push(marker);
}

// Sets the map on all markers in the array.
function setMapOnAll(map) {
  for (let i = 0; i < markers.length; i++) {
    markers[i].setMap(map);
  }
}

// Removes the markers from the map, but keeps them in the array.
function hideMarkers() {
  setMapOnAll(null);
}

// Shows any markers currently in the array.
function showMarkers() {
  setMapOnAll(map);
}

// Deletes all markers in the array by removing references to them.
function deleteMarkers() {
  hideMarkers();
  markers = [];
}

window.initMap = initMap;
index.js

/* 
 * Always set the map height explicitly to define the size of the div element
 * that contains the map. 
 */
#map {
  height: 100%;
}

/* 
 * Optional: Makes the sample page fill the window. 
 */
html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}

#floating-panel {
  position: absolute;
  top: 10px;
  left: 25%;
  z-index: 5;
  background-color: #fff;
  padding: 5px;
  border: 1px solid #999;
  text-align: center;
  font-family: "Roboto", "sans-serif";
  line-height: 30px;
  padding-left: 10px;
}
style.css

<html>
  <head>
    <title>Removing Markers</title>

    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script type="module" src="./index.js"></script>
  </head>
  <body>
    <div id="floating-panel">
      <input id="hide-markers" type="button" value="Hide Markers" />
      <input id="show-markers" type="button" value="Show Markers" />
      <input id="delete-markers" type="button" value="Delete Markers" />
    </div>
    <div id="map"></div>
    <p>Click on the map to add markers.</p>

    <!-- 
      The `defer` attribute causes the script to execute after the full HTML
      document has been parsed. For non-blocking uses, avoiding race conditions,
      and consistent behavior across browsers, consider loading using Promises. See
      https://developers.google.com/maps/documentation/javascript/load-maps-js-api
      for more information.
      -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly"
      defer
    ></script>
  </body>
</html>
index.html