let data; function getConfig() { if (data) return Promise.resolve(data); return fetch('config.json?nocache=' + new Date().getUTCMilliseconds()).then(response => { data = response.json(); return data; }).catch(error => { console.warn('web config file is missing so the template will be used'); return getDefaultConfig(); }); } function getDefaultConfig() { return fetch('config.template.json').then(function (response) { data = response.json(); return data; }); } export function enableMultiServer() { return getConfig().then(config => { return config.multiserver; }).catch(error => { console.log('cannot get web config:', error); return false; }); }