SOURCE

let book = {
    year: 2011,
    releaseDate: new Date(2011, 11, 1)
}

let jsonText = JSON.stringify(book);

let bookJustCopy = JSON.parse(jsonText);

let bookCopy = JSON.parse(jsonText, function(key, value){
    if (key == "releaseDate") {
        // 此时releaseDate属性的值只是一个字符串
        return new Date(value);
    } else {
        return value;
    }
});

let year = bookCopy.releaseDate.getFullYear();
console.log(year);