Array Data Types in JavaScript
An Array is a non-primitive data type in JavaScript. It represents a collection of elements, where each element can be of any data type, including other arrays.
What is an Array in JavaScript?
In JavaScript, an Array is a special type of object that represents a collection of elements. The elements can be of any data type, including other arrays. Arrays are used to store multiple values in a single variable. Each element in an array has a unique index, which is used to access the element. The index starts from 0 and goes up to length - 1, where length is the number of elements in the array.
Creating Arrays in JavaScript
You can create an array in JavaScript using the following syntax:
let numbers = [1, 2, 3, 4, 5];
let names = ['John', 'Doe', 'Jane', 'Smith'];
let mixed = [1, 'John', true, null, undefined];
In the above examples, we have created arrays of numbers, strings, and mixed data types.
Accessing Array Elements
You can access elements of an array using their index. The index starts from 0 for the first element and goes up to length - 1 for the last element.
let numbers = [1, 2, 3, 4, 5];
console.log(numbers[0]); // Output: 1
console.log(numbers[2]); // Output: 3
console.log(numbers[4]); // Output: 5
In the above example, we have accessed the first, third, and fifth elements of the numbers array using their indices.
Modifying Array Elements
You can modify elements of an array using their index.
let numbers = [1, 2, 3, 4, 5];
numbers[0] = 10;
console.log(numbers); // Output: [10, 2, 3, 4, 5]
In the above example, we have modified the first element of the numbers array and changed its value to 10.
Adding Array Elements
You can add elements to the end of an array using the push method.
let numbers = [1, 2, 3, 4, 5];
numbers.push(6);
console.log(numbers); // Output: [1, 2, 3, 4, 5, 6]
In the above example, we have added the number 6 to the end of the numbers array using the push method.
Deleting Array Elements
You can delete elements from an array using the delete operator or the splice method.
let numbers = [1, 2, 3, 4, 5];
delete numbers[2];
console.log(numbers); // Output: [1, 2, empty, 4, 5]
In the above example, we have deleted the third element of the numbers array using the delete operator. The element is replaced with empty, which is a placeholder for the deleted element.
Deleting Array Elements using pop Method
You can also delete elements from the end of an array using the pop method.
let numbers = [1, 2, 3, 4, 5];
numbers.pop();
console.log(numbers); // Output: [1, 2, 3, 4]
In the above example, we have deleted the last element of the numbers array using the pop method.
Arrays Style in JavaScript
There are different styles of arrays in JavaScript:
1. Dense Array
A dense array is an array in which the elements are stored in contiguous memory locations. It is the most common type of array in JavaScript.
for example:
let numbers = [1, 2, 3, 4, 5];
2. Sparse Array
A sparse array is an array in which the elements are not stored in contiguous memory locations. It contains empty slots, which are placeholders for the missing elements.
for example:
let numbers = [1, , 3, , 5];
3. Array-like Objects
Array-like objects are objects that have a length property and indexed elements, but they are not instances of the Array constructor.
for example:
let arrayLike = {
0: 'a',
1: 'b',
2: 'c',
length: 3
};
4. Typed Arrays
Typed arrays are a set of array-like objects that provide a way to work with binary data in JavaScript. They are used to represent raw binary data in memory and are used in various scenarios, such as working with WebGL, file I/O, and networking.
for example:
let buffer = new ArrayBuffer(16);
let int32Array = new Int32Array(buffer);
Typed Arrays in JavaScript
Typed arrays are a set of array-like objects that provide a way to work with binary data in JavaScript. They are used to represent raw binary data in memory and are used in various scenarios, such as working with WebGL, file I/O, and networking.
The following are the different types of typed arrays available in JavaScript:
1. Int8Array
The Int8Array represents an array of 8-bit signed integers.
for example:
let buffer = new ArrayBuffer(16);
let int8Array = new Int8Array(buffer);
2. Uint8Array
The Uint8Array represents an array of 8-bit unsigned integers.
for example:
let buffer = new ArrayBuffer(16);
let uint8Array = new Uint8Array(buffer);
3. Uint8ClampedArray
The Uint8ClampedArray represents an array of 8-bit unsigned integers clamped to 0-255.
for example:
let buffer = new ArrayBuffer(16);
let uint8ClampedArray = new Uint8ClampedArray(buffer);
4. Int16Array
The Int16Array represents an array of 16-bit signed integers.
for example:
let buffer = new ArrayBuffer(16);
let int16Array = new Int16Array(buffer);
5. Uint16Array
The Uint16Array represents an array of 16-bit unsigned integers.
for example:
let buffer = new ArrayBuffer(16);
let uint16Array = new Uint16Array(buffer);
6. Int32Array
The Int32Array represents an array of 32-bit signed integers.
for example:
let buffer = new ArrayBuffer(16);
let int32Array = new Int32Array(buffer);
7. Uint32Array
The Uint32Array represents an array of 32-bit unsigned integers.
for example:
let buffer = new ArrayBuffer(16);
let uint32Array = new Uint32Array(buffer);
8. Float32Array
The Float32Array represents an array of 32-bit floating-point numbers.
for example:
let buffer = new ArrayBuffer(16);
let float32Array = new Float32Array(buffer);
9. Float64Array
The Float64Array represents an array of 64-bit floating-point numbers.
for example:
let buffer = new ArrayBuffer(16);
let float64Array = new Float64Array(buffer);
- Array Literals: The array literal syntax
[]is the most common way to create arrays in JavaScript. - Array Elements: Arrays can contain elements of any data type, including other arrays.
- Accessing Array Elements: You can access array elements using their index, which starts from
0. - Modifying Array Elements: You can modify array elements using their index.
- Adding Array Elements: You can add elements to the end of an array using the
pushmethod. - Deleting Array Elements: You can delete elements from an array using the
deleteoperator or thesplicemethod. - Deleting Array Elements using
popMethod: You can delete elements from the end of an array using thepopmethod. - Array Styles: There are different styles of arrays in JavaScript, including dense arrays, sparse arrays, array-like objects, and typed arrays.
- Typed Arrays: Typed arrays are a set of array-like objects that provide a way to work with binary data in JavaScript.
- Array Methods: JavaScript provides various methods for working with arrays, such as
push,pop,shift,unshift,splice,slice,concat,join,reverse,sort,indexOf,lastIndexOf,includes,forEach,map,filter,reduce, andfind. - Array Properties: Arrays have various properties, such as
length,constructor, andprototype. - Array-like Objects: Array-like objects are objects that have a
lengthproperty and indexed elements, but they are not instances of theArrayconstructor. - Typed Arrays: Typed arrays are a set of array-like objects that provide a way to work with binary data in JavaScript.
- Array Buffers: Array buffers are used to represent raw binary data in memory and are used in various scenarios, such as working with WebGL, file I/O, and networking.
- Array Buffer Views: Array buffer views are used to read and write binary data to and from array buffers.
- Array Destructuring: Array destructuring is a convenient way to extract multiple elements from an array and assign them to variables.
- Array Spread Operator: The array spread operator (
...) is used to expand an array into individual elements.
Conclusion
In this tutorial, you learned about the array data type in JavaScript and how to create, access, modify, add, and delete array elements. You can use arrays to store multiple values in a single variable and perform various operations on the elements of the array.