Top 10 ways to get last element from an array in javascript


This is an short tutorial on multiple ways to get first element from an array

Let’s declare an array

let array=[12,1,8,9];

Array index always starts with index=0 and array.length returns the length of an array. that means array[0] returns first element, array[array.length-1] returns last element of an array.

Array.length property returns length of an array.

Following are Multiple ways, we can retrieve first element of an array in JavaScript For given input array above, Outut is first element from an array is 9.

select element using array index without mutating original array

As array.length returns the number of elements in it. Array always starts with zero index, So first element can be retrieved using below syntax.

console.log(array[0]);

This works on all browsers and simple way.

find method to get first element of an array with es6 lambda expressions

Array.find method returns the first single element for the given function,

Here lambda functions in es6 are for call-back functions

let firstElemet=array.find(element => element);
console.log(firstElemet) // 12 is returned

How can you get first index of an array using find method.

findIndex method works similar way of find method.

let firstIndex = array.findIndex(item => item)
console.log(firstIndex) // 0 is returned

This approach works if array contains all defined values

How do you select first element without mutating of original array?

Ecmascript (ES6) array slice method to get first element of an array

array.slice is an method in ES6 javascript. It returns shallow copy of an an array and creates a new array from start index to end index.

let array=[12,1,8,9];
console.log(array.length); //4 
console.log(array.slice(0,1)); // (1) [12]
console.log(array.slice(0,1)[0]); // 12
console.log(array.length); //4

with destructing assignment operators, The same can be simplified as follows

[firstElement] = array.slice(0,1);
console.log(firstElement); //12

Array destructing with ES6 example

latest ES6 provides feature destructing assignment operators, with this, First element can be easily retrieved.

let [firstElememt]=array;
console.log(firstElememt);

Using reverse method to get first element

This is also an simple approach by reversing an original array using reverse() method. This will return an array in reverse order.

Next, retrieve last element using pop() method

var reverseArray = array.reverse().pop; 
console.log(reverseArray[0]) // 12

Select first element using Third-party JavaScript

JavaScript has different third-party libraries like UnderscoreJs, Lodash and Ramda. These are utilities libraries provides lot of methods can be reused

The first function returns first element of an array.

_.last(array);

Lodash provides head method which also returns the first element from an array.

_.head(array);

This will be useful, if your project is already using those library.

It is simple and easy way to find first element

select first element with mutation of original array using shift method

shift method of an array returns first element, However original array is modified

Please see an example after calling shift(), Original array removes first element

let array=[12,1,8,9];
console.log(array) // [12,1,8,9]
let firstElement=array.shift(); 
console.log(firstElement)// 12
console.log(array) // [1,8,9]

This will be useful if you want to mutates original array.

How to get first element using Object values function

Object values method takes object enumerable properties and returns an array

It also takes an array and return the same an array

console.log(Object.values(array)[0]);

Conclusion

Multiple approaches are specified here, To sump up, you can take whichever approach fits to your application.

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