Syntax 862
Simple Values 862
Objects 862
Arrays 863
Parsing and Serialization 864
The JSON Object 865
Serialization Options 866
 Filtering Results 866
 String Indentation 867
 The toJSON() Method 868
Parsing Options 869
Summary 870

----------------------------------------------------

JSON.stringify(book, ["title", "edition"]);

let jsonText = JSON.stringify(book, (key, value) => {
 switch(key) {
  case "authors":
   return value.join(",")
  case "year":
   return 5000;
  case "edition":
   return undefined;
  default:
   return value;
 }
});

----------------------------------------------------

JSON.stringify(book, null, 4);

JSON.stringify(book, null, "--"); 

--------------------------------------------------

let book = {
 title: "Professional JavaScript",
 authors: [
  "Nicholas C. Zakas",
  "Matt Frisbie"
 ],
 edition: 4,
 year: 2017,
 toJSON: function() {
  return this.title;
 }
};
let jsonText = JSON.stringify(book);
console.log(jsonText); //"Professional JavaScript"

toJSON的执行优先级是最高的。

---------------------------------------------------

let book = {
 title: "Professional JavaScript",
 authors: [
  "Nicholas C. Zakas",
  "Matt Frisbie"
 ],
 edition: 4,
 year: 2017,
 releaseDate: new Date(2017, 11, 1)
};
let jsonText = JSON.stringify(book);
let bookCopy = JSON.parse(jsonText,
  (key, value) => key == "releaseDate" ? new Date(value) : value);
alert(bookCopy.releaseDate.getFullYear());