javascript 如何附加到 HTML5 localStorage？
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How to append to HTML5 localStorage?
提问by Lazer
I do a
我做一个
localStorage.setItem('oldData', $i("textbox").value);
to set the value of key oldDatato the value in a textbox.
将 keyoldData的值设置为文本框中的值。
The next time something is entered to the textbox, I want to append to the already existing oldData.
下次在文本框中输入内容时，我想附加到已经存在的oldData.
So, if I enter applesand then orangesin my textbox, my localStorage key oldDatashould look like this:
因此，如果我在文本框中输入apples和oranges，我的 localStorage 键oldData应如下所示：
Initially:
原来：
Key | Value
---------------------------
oldData | apples
Now:
现在：
oldData | apples oranges
How can I append? Is there an appendmethod provided?
我怎样才能追加？有提供append方法吗？
Or do I need to read the data first, append in javascript and then write back?
还是我需要先读取数据，在 javascript 中追加然后写回？
回答by Rob W
There's no appendfunction. It's not hard to write one though:
没有任何append功能。不过写一个也不难：
function appendToStorage(name, data){
var old = localStorage.getItem(name);
if(old === null) old = "";
localStorage.setItem(name, old + data);
}
appendToStorage('oldData', $i("textbox").value);
Note: It makes more sense to define a function appendon the localStorageobject. However, because localStoragehas a setter, this is not possible. If you were trying to define a function using localStorage.append = ..., the localStorageobject will interpret this attempt as "Save an object called appendin the Storage object".
注意：append在localStorage对象上定义一个函数更有意义。但是，因为localStorage有setter，这是不可能的。如果您尝试使用 定义函数localStorage.append = ...，则该localStorage对象会将这种尝试解释为“保存append在存储对象中调用的对象”。
回答by Nery Jr
It is not a good solution but it works and is performative.
这不是一个好的解决方案，但它有效并且具有执行力。
localStorage.setItem("fruit", "Apples");
localStorage.setItem("fruit", localStorage.getItem("fruit") + "Orange");
回答by XCS
I found this here:
我在这里找到了这个：
interface Storage {
readonly attribute unsigned long length;
DOMString? key(unsigned long index);
getter DOMString getItem(DOMString key);
setter creator void setItem(DOMString key, DOMString value);
deleter void removeItem(DOMString key);
void clear();
};
Seems like it only has getItem,setItem,removeItem,clear,key and length.
似乎它只有 getItem、setItem、removeItem、clear、key 和 length。
