How to get cached data with jquery

In web development, caching is a very important aspect to improve application performance. In jQuery, the framework also provides some convenient methods to help us obtain cached data, which will allow us to easily optimize our applications.

Next, we will learn how to use jQuery’s caching method to obtain data.

Use jQuery's cache method to obtain data

We can use the $.cache or $.data method to obtain cached data. The following is the specific use of these two methods:

1. Using $.cache

$.cache is an internal object used for caching, which stores all jQuery objects and their related data. Although it is a jQuery internal object, we can also use it to get cache data.

The following is a sample code that uses the $.cache method to obtain cached data:

var cachedData = $.cache[$.data($('#myElement')[0])];

Through the above code, we can see that the way to obtain cached data is quite simple. First, we use the $.data method to obtain the associated data of a jQuery object. Next, we use this associated data as an index to access the $.cache object. In this way, we can get the data associated with this jQuery object.

In specific applications, we can apply the above code where we need to access cached data, such as some operations that need to be performed repeatedly.

2. Using $.data

Similar to the $.cache method, we can also use the $.data method to obtain cached data. This method is more common and easier to use.

The following is a sample code that uses the $.data method to obtain cached data:

var cachedData = $('#myElement').data('cachedData');

Through the above code, we can see that the $.data method requires a parameter, which is used to store The key name of the data. In the above example, we use 'cachedData' as the key name to store the cached data. We can call this method again where we need to use cached data to get the data.

It should be noted that the $.data method can only access cached data belonging to the current jQuery object by default. If we need to access the cached data of a parent or ancestor element, we need to specify an accessor function to get it.

The following is a sample code that uses accessor functions to get cached data:

var cachedData = $('myElement').parents('.myParent').eq(0).data('cachedData', function() {
    return cachedData;
});

In the above code, we use the parents method to get the parent element and set a filter To make sure we get the correct elements. Next, we use the data method to get the cached data and pass a function as a parameter to the data method. This function returns the previously cached data, so that the cached data of the parent element can be included.

Summary

The above are two methods of obtaining cached data in jQuery. They are very simple, easy to understand and use.

In practice, we can choose the appropriate method according to our needs to improve the performance of our application. When we need to access data repeatedly or perform calculations on data, using cached data is a very effective way. Therefore, mastering the method of obtaining cached data in jQuery will be of great help to our web development work.

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