@marfle/react-leaflet-nmscale/dist/esm/leafletnmscale.js

Nautical mile scale for react-leaflet

import { Control, DomUtil } from 'leaflet';
const NmScaleControl = Control.Scale.extend({
  _addScales: function (options, className, container) {
    Control.Scale.prototype._addScales.call(this, options, className, container);
    if (options.nautical) {
      this._nScale = DomUtil.create('div', className, container);
    }
  },
  _updateScales: function (maxMeters) {
    Control.Scale.prototype._updateScales.call(this, maxMeters);
    if (this.options.nautical && maxMeters) {
      this._updateNautical(maxMeters);
    }
  },
  _updateNautical: function (maxMeters) {
    const maxNm = maxMeters / 1852;
    let nm;
    if (maxMeters < 185) {
      nm = Math.round(maxNm * 100) / 100;
    } else if (maxMeters < 1852) {
      nm = Math.round(maxNm * 10) / 10;
    } else {
      nm = this._getRoundNum(maxNm);
    }
    let label = nm + 'nm';
    this._updateScale(this._nScale, label, nm / maxNm);
  }
});
export default NmScaleControl;