maps.onRemove.patch.js

// The following code patches google.maps API since in `onRemove` they don't check for null
// sometimes this conflicts with the way React handle DOM.
const PATCH_ONREMOVE = Symbol.for('Patch onRemove');

function waitForGoogleThenPatch() {
  /* global google */
  if (typeof google === 'undefined') {
    window.requestAnimationFrame(waitForGoogleThenPatch);
  } else {
    const Marker = google.maps.Marker;
    if (Marker[PATCH_ONREMOVE]) return;
    Marker[PATCH_ONREMOVE] = true;
    const patch = (onRemove) => {
      return function onRemovePatched(...args) {
        let temp = document.createElement('div');

        if (!this.labelDiv_.parentNode) {
          temp.appendChild(this.labelDiv_);
        }
        if (!this.eventDiv_.parentNode) {
          temp.appendChild(this.eventDiv_);
        }
        if (!this.listeners_) {
          this.listeners_ = [];
        }
        onRemove.call(this, ...args);
        temp = null;
      };
    };

    Marker.prototype.setMap = ((setMap) => {
      return function setMapPatched(...args) {
        if (this.label) {
          const proto = Object.getPrototypeOf(this.label);
          if (!proto[PATCH_ONREMOVE]) {
            proto[PATCH_ONREMOVE] = true;
            proto.onRemove = patch(proto.onRemove);
          }
        }

        setMap.call(this, ...args);
      };
    })(Marker.prototype.setMap);
  }
}

if (typeof window !== 'undefined' && 'requestAnimationFrame' in window) {
  window.requestAnimationFrame(waitForGoogleThenPatch);
}
/// --- End of patch ---