javascript - 添加键/值对失败，对象分配

Question

我有一个对象存储在本地存储中。我想检索对象并向其添加键/值项。这是代码

 var testObject = { 'one': 1, 'two': 2, 'three': 3 };

// Put the object into storage
localStorage.setItem('testObject', JSON.stringify(testObject));

// Retrieve the object from storage
var retrievedObject = localStorage.getItem('testObject');

var newdata = JSON.parse(retrievedObject);
var obj2 = {"four":"4"};
Object.assign(newdata, obj2);

$.each(JSON.parse(retrievedObject), function (index, value) {
  console.log(index+"  "+value);
});

新项目未添加到 testObject。如何将项目添加到现有对象？

Answer 1

您正在成功更改 newdata 但您没有使用它。相反，您再次调用 JSON.parse(retrievedObject)。

var testObject = { 'one': 1, 'two': 2, 'three': 3 };

// Put the object into storage
// Just use a variable because we cant use localstorage on snippet
var storage = JSON.stringify(testObject);

// Retrieve the object from storage
var retrievedObject = storage;

var newdata = JSON.parse(retrievedObject);
var obj2 = {"four":"4"};
Object.assign(newdata, obj2);

$.each(newdata, function (index, value) {
  console.log(index+"  "+value);
});

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