javascript将json对象推送到数组

Question

I have the following:

var cookie = $.cookie("Test_cookie");
var items = cookie ? eval("([" + cookie + "])") : [];
var jsonObj = { packageId: "11", machineId: "1", operationType: "Download" };
items.push(jsonObj);
$.cookie(cookieName, JSON.stringify(items), { expires: 1, path: '/' });

result:

[{"packageId":"11","machineId":"1","operationType":"Download"}]

which is correct.

However, when I run it the second time I want to append new object to items but json gets messed up (notice extra "["):

var jsonObj = { packageId: "11", machineId: "1", operationType: "Download" };
items.push(jsonObj);
$.cookie(cookieName, JSON.stringify(items), { expires: 1, path: '/' });

result:

[[{"packageId":"11","machineId":"1","operationType":"Download"}],{"packageId":"11","machineId":"1","operationType":"Download"}]

and it should be:

[{"packageId":"11","machineId":"1","operationType":"Download"},{"packageId":"11","machineId":"1","operationType":"Download"}]

what gives?

Answer 1

Your mistake is near

var items = cookie ? eval("([" + cookie + "])") : [];

Just do

var items = cookie ? eval(cookie) : [];