如何使用json.stringify在Cookie中正确存储对象数组？
[英]How to properly store an array of objects in a cookie using json.stringify?
问题描述
I'm trying to store an array of objects in a cookie using JSON.Stringify but I'm having a problem when I parse the cookie and try to push a new object to the array to then stringify it again. 
我正在尝试使用JSON.Stringify在cookie中存储对象数组，但是当我解析cookie并尝试将新对象推入数组然后再次对其进行字符串化时遇到了问题。 It tells me that comments.push is not a function. 它告诉我comments.push不是函数。
var comments = []; var myData = 0; function setCookie(cname, cvalue, exdays) { var d = new Date(); d.setTime(d.getTime() + (exdays*24*60*60*1000)); var expires = "expires="+d.toUTCString(); document.cookie = cname + "=" + cvalue + "; " + expires; } function getCookie(cname) { var name = cname + "="; var ca = document.cookie.split(';'); for(var i=0; i<ca.length; i++) { var c = ca[i]; while (c.charAt(0)==' ') c = c.substring(1); if (c.indexOf(name) == 0) return c.substring(name.length, c.length); } return ""; } function checkCookie() { var commentAux = getCookie("myComments"); if (commentAux != "") { //alert("Welcome again " + user); return true; } else { return false; } } function validateComment() { var x = document.forms["commentForm"]["commentSection"].value; if (x == null || x == "") { alert("There's nothing to comment, write something to proceed."); return false; } else { var comment = { firstName:"Name", lastName:"Surname", text:x }; if (checkCookie() == false) { setCookie("myComments", JSON.stringify(comment), 1); } else { myData = getCookie("myComments"); comments = JSON.parse(myData); alert(comments); comments.push(comment); setCookie("myComments", JSON.stringify(comments), 1); } } alert(comments.length); }
<!DOCTYPE html> <html> <head> <title>Facebook Simulator by Azael Alanis</title> <link rel="stylesheet" type="text/css" href="style.css"> <script src="javascript.js"></script> </head> <body> <img src="facebook-banner.png" alt="Facebook-Banner" style="height:100px;width:800px"> <div id="section"> <form name="commentForm" onsubmit="validateComment()"> <input type="text" name="commentSection" placeholder="What's on your mind?"><button class="buttonText">Enviar</button> </form> </div> </body> </html>
What could be the problem? 可能是什么问题呢？ I just want to parse my cookie -> add new object to array -> stringify it again 我只想解析我的cookie->将新对象添加到数组->再对其进行字符串化
Thanks 谢谢
2 个解决方案
解决方案1
1 2015-02-01 23:40:20
This is your problem: 这是你的问题：
comments = JSON.parse(myData);
comments.push(comment);
You probably meant to do 你可能想做
var comment = JSON.parse(myData);
comments.push(comment);
Since JSON.parse(myData) returns a comment object. 由于JSON.parse(myData)返回一个注释对象。
解决方案2
1 已采纳 2015-02-01 23:42:27
You use this code: 您使用以下代码：
var comment = { /* ... */ };
if (checkCookie() == false) {
setCookie("myComments", JSON.stringify(comment), 1);
} else {
comments = JSON.parse(getCookie("myComments"));
comments.push(comment);
setCookie("myComments", JSON.stringify(comments), 1);
}
The problem is that initially you store the object comment instead of an array containing it. 问题在于，最初存储对象comment而不是包含对象comment的数组。
Therefore, the next time, when you attempt to push another comment , you can't. 因此，下一次，当您尝试发送其他comment ，您将无法执行。
Try the following instead: 请尝试以下操作：
var comment = { /* ... */ };
if (checkCookie() == false) {
setCookie("myComments", JSON.stringify([comment]), 1); // <-- array
} else {
comments = JSON.parse(getCookie("myComments"));
comments.push(comment);
setCookie("myComments", JSON.stringify(comments), 1);
}
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