![]() With the general function behavior covered, let’s take a look at some examples of how the splice() function works in practice. If there are no items specified, then items will only be deleted from the array. These parameters are all of the items that will be added to the array beginning at the start index. ![]() The rest of the parameters from the third parameter onward are named item1, item2, and so on up to itemN. When this parameter has a negative value or a value of 0, no items will be deleted from the array. This behavior will also occur if the parameter value is larger than the number of items that exist from the start index to the end of the array. Doing so will result in all items from the start index to the end of the array being deleted. As it is the first optional parameter, it is possible to omit this value in any splice() function calls. The second parameter is the deleteCount parameter, and it is an integer indicating the number of items that should be deleted from the array beginning at the start index. If the parameter has such a large negative value that the sum of the parameter value and the length of the array results in a negative number, then the value of the start parameter will automatically be set to 0. This means that a parameter value of -3 would actually result in the value being 3 less than the length of the array ( Array.length + -3). When this parameter has a negative value, the value will be counted from the end of the array instead of from the beginning. In cases where this is true, the function will only add the specified items to the array and no items will be deleted from the array. When this parameter has a value greater than the length of the array, the value will automatically be set to the length of the array. The splice() function will work differently depending on the specified value of this parameter. The first parameter is the start parameter, and it is the index at which the array will begin to be changed. The splice() function is able to take an unlimited number of parameters with only the first parameter being required and all parameters after that being optional. This means that your logic should anticipate a change in the size of the array and be able to handle such a situation accordingly. One very important thing to remember when using the splice() function is that the length of the array may be different once the function has completed if the specified number of items to delete from the array and the specified number of items to add to the array are different. If you choose to use this function, keep in mind that you will not be able to maintain the original array without making a completely new copy of it beforehand. Not only does this function produce a completely new array, but it also modifies the original array on which the splice() function was called. Any items that are deleted from the original array are returned in a completely new array upon function completion. The splice() function provides the ability to change the contents of an array, both by deleting existing items from the array and by adding new items to the array. One of those useful functions that will be explored in this article is the splice() function. Now, the need for such homegrown implementations has been eliminated and replaced with all of these new functions. One of the major advantages of these new functions is that they provide developers with a set of functionality that they would have previously had to implement on their own with each new codebase that they encountered. ![]() Over the last several years there have been a wide variety of functions that have been added to the Javascript Array global object that offer developers new and exciting possibilities when it comes to writing code that works with arrays.
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