[英]Storing data with help of localstorage
I am storing localstorage
data in an array. 我将localstorage
存储数据存储在数组中。 My code is: 我的代码是:
var a;
//is anything in localstorage?
if (localStorage.getItem('session') === null) {
a = [];
} else {
// Parse the serialized data back into an array of objects
a = JSON.parse(localStorage.getItem('session'));
}
// Push the new data (whether it be an object or anything else) onto the array
a.push(data);
document.write(a + "<br>")
// Re-serialize the array back into a string and store it in localStorage
localStorage.setItem('session', JSON.stringify(a));
where data
is: data
在哪里:
var data = {name: "abc", place: "xyz"}
On every page refresh, my data is getting multiplied like this: 每次刷新页面时,我的数据都会像这样成倍增加:
[{name: "abc", place: "xyz"}, {name: "abc", place: "xyz"}, {name: "abc", place: "xyz"}, {name: "abc", place: "xyz"}]
I want to store data only if value of data
changes means instead of {name: "abc", place: "xyz"}
, I have {name: "ijk", place: "uvx"}
. 我想存储的数据,仅当值data
的变化意味着不是{name: "abc", place: "xyz"}
我有{name: "ijk", place: "uvx"}
How can I avoid data getting multiplied on each page refresh? 如何避免每次刷新时数据倍增?
You have to look into a
before inserting new data. 你必须寻找到a
插入新的数据之前。
if (!a.some(filterData(data)) {
a.push(data);
}
function filterData(data) {
return function(item) {
return item.name === data.name && item.place === data.place;
};
}
You could achieve the same thing with a loop: 您可以通过循环实现相同的目的:
var found = false;
for (var i = a.length; i--;) {
if (a[i].name === data.name && a[i].place === data.place) {
found = true;
break;
}
}
if (!found) {
a.push(data);
}
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