The JavaScript Array `filter()` Method – onlinecode

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2 years ago

The JavaScript Array `filter()` Method – onlinecode

In this post, we will give you information about The JavaScript Array `filter()` Method – onlinecode. Here we will give you detail about The JavaScript Array `filter()` Method – onlinecode And how to use it also give you a demo for it if it is necessary.

The Array#filter() function in JavaScript returns a new array with all the
elements from the original array that the given callback returns truthy for.

For example, given an array of numbers 1-10, below is how you can use filter() to
return an array of even numbers.

const nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

nums.filter(function isEven(num) {
  return num % 2 === 0;
}); // [2, 4, 6, 8, 10]

The filter() function returns a new array whose elements are the elements of
nums for which isEven() returned true.

The `index` Argument

JavaScript calls the filter() callback with 3 arguments. The first argument is
the element in the array, and the 2nd argument is the index in the array.

For example, below is how you can get an array with only the odd indexes of the original
array:

const names = [
  'James',
  'John',
  'Robert',
  'Michael',
  'William'
];

names.filter(function isOddIndex(el, index) {
  return index % 2 === 1;
}); // ['John', 'Michael']

JavaScript Fundamentals for The JavaScript Array `filter()` Method

JavaScript is a programming language that is used to create interactive web pages. It is a client-side scripting language, which means that it runs on the user’s browser. JavaScript can be used to add animation, interactivity, and functionality to web pages.

Here are some of the fundamentals of JavaScript:

Variables: Variables are used to store data. They are declared using the var keyword.
Data types: JavaScript has a variety of data types, including strings, numbers, booleans, objects, and arrays.
Operators: Operators are used to perform operations on data.
Control flow statements: Control flow statements allow you to control the order in which your code is executed.
Functions: Functions are blocks of code that can be reused.
Objects: Objects are used to store data in key-value pairs.
Arrays: Arrays are used to store data in a sequential order.
Events and event handlers: Events are notifications that are sent by the browser when something happens, such as when the user clicks on an element or moves the mouse over an element. Event handlers are functions that are called in response to an event.
DOM manipulation: The Document Object Model (DOM) is a tree-like structure that represents the elements of a web page. JavaScript can be used to manipulate the DOM to change the appearance or behavior of a web page.

The JavaScript Array `filter()` Method – onlinecode

The index Argument

The `index` Argument