JSON NaN bug
NaN is not valid in JSON
JSON
JSON {Symbol(Symbol.toStringTag): "JSON", parse: ƒ, stringify: ƒ}parse: ƒ parse()stringify: ƒ stringify()Symbol(Symbol.toStringTag): "JSON"__proto__: Object
obj = {score: NaN}
{score: NaN}score: NaN__proto__: Object
JSON.stringify(obj);
"{"score":null}"
JSON.parse(JSON.stringify(obj))
{score: null}score: null__proto__: Object
{"score": NaN}