javascript array splice not working as expected

Javascript array splice not working as expected how to#

This can continue until there is no index 2 anymore. If we don’t define the second parameter, every element starting from the given index will be removed from the array: only index 0 and 1 are still thereĪs a second example, I give the second parameter as 1, so elements starting from index 2 will be removed one by one each time we call the splice ( )method:Īfter 1st call: 3 is removed so “hello world” has now index 2Īfter 2nd call: This time, “hello world” is removed as index: 2 Elements which have a smaller index number from the given index won’t be removed:Īrray.splice(2) // Every element starting from index 2, will be removed Index is the starting point for removing elements.

Javascript array splice not working as expected how to#

Let’s see how to add and remove elements with splice( ): Removing Elementsįor removing elements, we need to give the index parameter, and the number of elements to be removed:

The splice( ) method changes an array, by adding or removing elements from it. This naming similarity often confuses developers. The name of this function is very similar to slice( ).

Now let’s see the result: Slice array and assign the members to newArray newArray variable is an array now, and the original one remains the same Important Note: the Slice( ) method can also be used for strings. Let newArray = array.slice(0, 3) // Return value is also an arrayįinally, I assign the sliced Array to the newArray variable. That’s why I call the second parameter “until”.

array -> 1 // includedĪrray -> 'hello world' // not included The slice( ) method doesn’t include the last given element. When I want to slice the first three elements, I must give the until parameter as 3. Since the first element of an array is always indexed at 0, I start slicing “from”0. Until: Slice the array until another element indexįor example, I want to slice the first three elements from the array above.From: Slice the array starting from an element index.The slice( ) method copies a given part of an array and returns that copied part as a new array. An array with different data types: string, numbers, and a boolean. Now let’s declare another array with different data types. Let arrayDefinition = // Array declaration in JS You can see below how to declare an array in JavaScript: Then we use some JS methods like slice () & splice (). Sometimes we need to do operations on those arrays. But the difference is that JS arrays can contain different type of data at once. Like in other programming languages, we use arrays to store multiple data in JS. If you prefer, you can also watch the video version below:įirstly, you need to understand how JavaScript arrays work. You can find a summary of each method in the end. I advise students and junior developers to read this article carefully because these three methods can also be asked in JOB INTERVIEWS. Perhaps because their naming is so similar they are often confused, even among experienced developers. I would like to explain three of them in this article: the slice(), splice() and split()methods. JavaScript built-in methods help us a lot while programming, once we understand them correctly.