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JavaScript Arrays

·282 words·2 mins·
Programming Javascript Arrays Data-Structures Web-Development
Table of Contents

JavaScript Arrays
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An array is a data structure that allows you to store multiple values in a single variable. In JavaScript, arrays are versatile and can hold elements of different data types.

Creating Arrays
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You can create an array using the array literal syntax [] or the Array constructor.

// Array literal
let fruits = ["Apple", "Banana", "Cherry"];
console.log(fruits);

// Array constructor
let numbers = new Array(1, 2, 3, 4, 5);
console.log(numbers);

Accessing Array Elements
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Array elements are accessed using zero-based indices.

let fruits = ["Apple", "Banana", "Cherry"];
console.log(fruits[0]); // "Apple"
console.log(fruits[1]); // "Banana"

Common Array Methods
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JavaScript provides a rich set of methods for working with arrays.

  • push(): Adds one or more elements to the end of an array.
  • pop(): Removes the last element from an array.
  • shift(): Removes the first element from an array.
  • unshift(): Adds one or more elements to the beginning of an array.
  • forEach(): Executes a provided function once for each array element.
  • map(): Creates a new array with the results of calling a provided function on every element.
  • filter(): Creates a new array with all elements that pass the test implemented by the provided function.
  • reduce(): Executes a reducer function on each element of the array, resulting in a single output value.

Examples of Array Methods
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let numbers = [1, 2, 3, 4, 5];

// forEach
numbers.forEach(num => {
  console.log(num * 2);
});

// map
let doubled = numbers.map(num => num * 2);
console.log(doubled); // [2, 4, 6, 8, 10]

// filter
let evenNumbers = numbers.filter(num => num % 2 === 0);
console.log(evenNumbers); // [2, 4]

// reduce
let sum = numbers.reduce((accumulator, currentValue) => accumulator + currentValue, 0);
console.log(sum); // 15

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