Function isLegalKey

docs/app/js/sanddance-app.js:106630–106630

(key1)

    return _ === Object(_);
}
const isLegalKey = (key1)=>key1 !== "__proto__";
function mergeConfig(...configs) {
    return configs.reduce((out, source)=>{
        for(const key2 in source)if (key2 === "signals") // for signals, we merge the signals arrays