We can use the concat() method to add elements to an array without mutating or altering the original array. How to push elements into an array with the concat() method Splice in JavaScript and when to use them in this detailed article. It does not remove any elements, so it returns an empty array. Note that the previous methods returned the length of the new array, but the splice method changes the original array. Just as we did for other methods, we can also add more than one element: const countries = The following parameter(s) or element(s) may be more than one, as these are the elements we want to add to the array at the specified position.įor example, let's place "Kenya" after "Ghana" in our countries array: const countries =.If we want to add to the array, we set the second argument to zero ( 0), instructing the splice() method not to delete any array elements. If there are multiple elements, it specifies where the elements inserted will start. The start_position specifies the index of where we want the new elements to be inserted in the array.In that case, we will use the splice() method with the following syntax: Array.splice(start_position, 0, new_element.) Suppose we want to add "Kenya," which, according to alphabetical order, should be placed in the second position, index 1 (after Ghana and before Nigeria). This section will cover how to use this method to add an element to a specific location.įor example, consider the following array of countries, which contains three elements (countries) arranged alphabetically: const countries = The splice() method is a general-purpose method for changing the contents of an array by removing, replacing, or adding elements in specified positions of the array. Well, you can do it with the splice() method. But you might wonder how to add an element to a specific location within an array. So far, we've only seen how to add an element to the beginning or end of an array. How to push to a specified location in an array with the splice() method Let countriesLength = countries.push("Kenya") Let's try the same example again, but this time add them to the end of the array using the push() method: const countries = Īnd like we said, we can use it to get the length of the new array: const countries = It returns the length of the new array and, like the unshift() method, can be used to add more than one element. The push() method is similar to the unshift() method as it adds an element to the end of an array rather than the beginning. How to push to the end of an array with the push() method Let countriesLength = countries.unshift("South Africa", "Mali", "Kenya") In our explanation of the unshift() method, we also stated that it returns the length of the new array, which is true: const countries = If we have an array of countries and want to add a country before "Nigeria," which is currently at the first index 0, we can do so with the unshift() method, as shown below: const countries = Ĭonsole.log(countries) // Īs we said, we can also add more than one element using the unshift() method: const countries = Ĭountries.unshift("South Africa", "Mali", "Kenya") In JavaScript, you use the unshift() method to add one or more elements to the beginning of an array and it returns the array's length after the new elements have been added. How to push to the start of an array with the unshift() method And finally, when you want to maintain your original array, you can use the concat() method.
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