demarches-normaliennes/app/assets/javascripts/api_carto/lib/leaflet.spin.js

function onDocumentReady(){
    if (typeof L != 'undefined') {
        L.SpinMapMixin = {
            spin: function (state, options) {
                if (!!state) {
                    // start spinning !
                    if (!this._spinner) {
                        this._spinner = new Spinner(options).spin(this._container);
                        this._spinning = 0;
                    }
                    this._spinning++;
                }
                else {
                    this._spinning--;
                    if (this._spinning <= 0) {
                        // end spinning !
                        if (this._spinner) {
                            this._spinner.stop();
                            this._spinner = null;
                        }
                    }
                }
            }
        };

        L.Map.include(L.SpinMapMixin);

        L.Map.addInitHook(function () {
            this.on('layeradd', function (e) {
                // If added layer is currently loading, spin !
                if (e.layer.loading) this.spin(true);
                if (typeof e.layer.on != 'function') return;
                e.layer.on('data:loading', function () { this.spin(true); }, this);
                e.layer.on('data:loaded',  function () { this.spin(false); }, this);
            }, this);
            this.on('layerremove', function (e) {
                // Clean-up
                if (e.layer.loading) this.spin(false);
                if (typeof e.layer.on != 'function') return;
                e.layer.off('data:loaded');
                e.layer.off('data:loading');
            }, this);
        });
    }
}

$(document).ready(onDocumentReady);
$(document).on('page:load', onDocumentReady);