Method handler

docs/app/js/sanddance-app.js:9528–9530

(n, v)

                    this.vegaViewGl = new _vegaDeckGl.ViewGl(runtime, config).renderer("deck.gl").initialize(this.element);
                    yield this.vegaViewGl.runAsync();
                    const handler = (n, v)=>{
                        this._characterSet.resetCharacterSet(true);
                    };
                    this.vegaSpec.signals.forEach((s)=>{
                        this.vegaViewGl.addSignalListener(s.name, handler);
                    });