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Articles by AmitDiwan
Page 401 of 840
How to remove blank (undefined) elements from JavaScript array - JavaScript
When working with JavaScript arrays, you may encounter sparse arrays containing empty slots (undefined elements). These gaps can occur when elements are deleted or when arrays are created with missing values. const arr = [4, 6, , 45, 3, 345, , 56, 6]; console.log(arr); console.log("Length:", arr.length); [ 4, 6, , 45, 3, 345, , 56, 6 ] Length: 9 We need to remove only the undefined and empty values, not all falsy values like 0, false, or empty strings. Method 1: Using splice() with for loop Use a for loop to ...
Read MoreProgram to retrieve the text contents of the user selection using JavaScript.
In JavaScript, you can retrieve the text contents of a user's selection using the window.getSelection() method. This is useful for creating text highlighting features, copy functionality, or interactive reading applications. How It Works The window.getSelection() method returns a Selection object representing the range of text selected by the user. You can convert this to a string using the toString() method. Example Text Selection Demo body ...
Read MoreHow to create a function which returns only even numbers in JavaScript array?
Here, we need to write a function that takes one argument, which is an array of numbers, and returns an array that contains only the numbers from the input array that are even. So, let's name the function as returnEvenArray, the code for the function will be − Example const arr = [3, 5, 6, 7, 8, 4, 2, 1, 66, 77]; const returnEvenArray = (arr) => { return arr.filter(el => { return el % 2 === 0; }) }; ...
Read MoreHow to add properties from one object into another without overwriting in JavaScript?
When merging objects in JavaScript, you often want to add properties from one object to another without overwriting existing values. This preserves the original object's data while incorporating new properties. The Problem Consider these two objects where some properties overlap: var first = {key1: 100, key2: 40, key3: 70}; var second = {key2: 80, key3: 70, key4: 1000}; console.log("First object:", first); console.log("Second object:", second); First object: { key1: 100, key2: 40, key3: 70 } Second object: { key2: 80, key3: 70, key4: 1000 } We want to add key4 from ...
Read MoreSum similar numeric values within array of objects - JavaScript
Suppose, we have an array of objects like this — const arr = [ {"firstName":"John", "value": 89}, {"firstName":"Peter", "value": 151}, {"firstName":"Anna", "value": 200}, {"firstName":"Peter", "value": 22}, {"firstName":"Anna", "value": 60} ]; We are required to write a JavaScript function that takes in one such array and combines the value property of all those objects that have similar value for the firstName property. Therefore, for the above array, the output should look like — const output = [ ...
Read MoreJavaScript JSON Arrays
JSON arrays are ordered lists of values enclosed in square brackets. In JavaScript, you can access and manipulate JSON arrays just like regular JavaScript arrays. Syntax { "arrayName": ["value1", "value2", "value3"] } Basic JSON Array Structure Here's how a JSON object with an array property looks: JSON Array Example let obj = { ...
Read MoreCircle coordinates to array in JavaScript
In JavaScript, you can generate circle coordinates by using trigonometric functions to calculate points around a circle's circumference. This is useful for animations, graphics, and positioning elements in circular patterns. How Circle Coordinates Work A circle's coordinates are calculated using the parametric equations: X coordinate: centerX + radius × cos(angle) Y coordinate: centerY + radius × sin(angle) By dividing the circle into equal steps and calculating coordinates at each angle, we can create an array of points around the circle. Example ...
Read MoreReverse a number in JavaScript
Our aim is to write a JavaScript function that takes in a number and returns its reversed number. For example, reverse of 678 is: 876 There are multiple approaches to reverse a number in JavaScript. Let's explore the most common methods. Method 1: Using String Conversion The most straightforward approach converts the number to a string, reverses it, and converts back to a number: const num = 124323; const reverse = (num) => parseInt(String(num) .split("") .reverse() .join(""), 10); console.log(reverse(num)); ...
Read MoreUpdate array of objects with JavaScript?
In JavaScript, you can update an array of objects by modifying existing objects or adding new ones. This is commonly done using methods like push(), splice(), or array methods like map() and find(). Let's say we have the following array of objects: var studentDetails = [ { firstName: "John", listOfSubject: ['MySQL', 'MongoDB']}, {firstName: "David", listOfSubject: ['Java', 'C']} ]; console.log("Initial array:", studentDetails); Initial array: [ { firstName: 'John', listOfSubject: [ 'MySQL', 'MongoDB' ] }, { firstName: 'David', listOfSubject: [ 'Java', 'C' ] } ] ...
Read MoreSquared sum of n odd numbers - JavaScript
We are required to write a JavaScript function that takes in a Number, say n, and finds the sum of the square of first n odd natural Numbers. For example, if the input number is 3, we need to find the first 3 odd numbers (1, 3, 5) and calculate the sum of their squares: 1² + 3² + 5² = 1 + 9 + 25 = 35 Understanding the Pattern The first n odd natural numbers follow the pattern: 1, 3, 5, 7, 9... The formula for the i-th odd number is (2 * i) - 1. Example const num = 3; const squaredSum = num => { let sum = 0; for(let i = 1; i
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