Why do json attribute names need double quotes (personal guess)_javascript skills

Reason 1:

More standardized and easier to analyze

Reason 2:

Avoid incompatibility issues caused by keywords such as class

Reason 3:

Probably the most obscure one:

var a = 00; var b = {00: 12}; a in b; --> true
var a = 0; var b = {'00': 12}; a in b; --> false

Personally guess that if the attribute name of the js object is non-string type, type conversion will be performed first, but unexpected values ​​may appear in this process. Although this is only an isolated case, it is still very useful to develop a good habit. Necessary