javascript - 在HTML5 localStorage中存储对象(Storing Objects in HTML5 localStorage)

Question

I'd like to store a JavaScript object in HTML5 localStorage , but my object is apparently being converted to a string.

(我想将JavaScript对象存储在HTML5 localStorage ，但是我的对象显然正在转换为字符串。)

I can store and retrieve primitive JavaScript types and arrays using localStorage , but objects don't seem to work.

(我可以使用localStorage存储和检索原始JavaScript类型和数组，但是对象似乎无法正常工作。)

Should they?

(应该吗)

Here's my code:

(这是我的代码：)

var testObject = { 'one': 1, 'two': 2, 'three': 3 };
console.log('typeof testObject: ' + typeof testObject);
console.log('testObject properties:');
for (var prop in testObject) {
    console.log('  ' + prop + ': ' + testObject[prop]);
}

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

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

console.log('typeof retrievedObject: ' + typeof retrievedObject);
console.log('Value of retrievedObject: ' + retrievedObject);

The console output is

(控制台输出为)

typeof testObject: object
testObject properties:
  one: 1
  two: 2
  three: 3
typeof retrievedObject: string
Value of retrievedObject: [object Object]

It looks to me like the setItem method is converting the input to a string before storing it.

(在我看来， setItem方法在存储输入之前将输入转换为字符串。)

I see this behavior in Safari, Chrome, and Firefox, so I assume it's my misunderstanding of the HTML5 Web Storage spec, not a browser-specific bug or limitation.

(我在Safari，Chrome和Firefox中看到了这种行为，因此我认为这是我对HTML5 Web存储规范的误解，而不是浏览器特定的错误或限制。)

I've tried to make sense of the structured clone algorithm described in http://www.w3.org/TR/html5/infrastructure.html .

(我试图弄清http://www.w3.org/TR/html5/infrastructure.html中描述的结构化克隆算法。)

I don't fully understand what it's saying, but maybe my problem has to do with my object's properties not being enumerable (???)

(我不完全明白这是什么意思，但也许我的问题与我的对象的属性不可枚举有关（???）)

Is there an easy workaround?

(有一个简单的解决方法吗？)

---

Update: The W3C eventually changed their minds about the structured-clone specification, and decided to change the spec to match the implementations.

(更新：W3C最终改变了对结构化克隆规范的想法，并决定更改规范以匹配实现。)

See https://www.w3.org/Bugs/Public/show_bug.cgi?id=12111 .

(参见https://www.w3.org/Bugs/Public/show_bug.cgi?id=12111 。)

So this question is no longer 100% valid, but the answers still may be of interest.

(因此，此问题不再100％有效，但答案可能仍然很有趣。)

  ask by Kristopher Johnson translate from so

Answer 1

Looking at the Apple , Mozilla and Mozilla again documentation, the functionality seems to be limited to handle only string key/value pairs.

(再次查看Apple ， Mozilla和Mozilla文档，该功能似乎仅限于处理字符串键/值对。)

A workaround can be to stringify your object before storing it, and later parse it when you retrieve it:

(一种解决方法是在存储对象之前先对其进行字符串化 ，然后在检索它时对其进行解析：)

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');

console.log('retrievedObject: ', JSON.parse(retrievedObject));