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Articles by AmitDiwan
Page 417 of 840
How to import and export a module/library in JavaScript?
Note − To run this example you will need to run a localhost server. JavaScript modules allow you to break code into separate files and share functionality between them using export and import statements. This promotes code reusability and better organization. Example INDEX.html Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; ...
Read MoreDe-structuring an object without one key
Object destructuring with the rest operator (...) allows you to extract specific properties while collecting the remaining properties into a new object. This technique is useful when you want to exclude certain keys from an object. Syntax const { keyToExclude, ...remainingKeys } = originalObject; Example: Excluding One Key Object Destructuring body { ...
Read MoreCount unique elements in array without sorting JavaScript
When working with arrays containing duplicate values, counting unique elements is a common task. Let's explore different approaches to count unique elements in an array without sorting it first. Consider this sample array with duplicate values: const arr = ['Cat', 'Dog', 'Cat', 'Elephant', 'Dog', 'Grapes', 'Dog', 'Lion', 'Grapes', 'Lion']; console.log('Original array:', arr); Original array: ['Cat', 'Dog', 'Cat', 'Elephant', 'Dog', 'Grapes', 'Dog', 'Lion', 'Grapes', 'Lion'] Using Array.reduce() and lastIndexOf() This approach uses lastIndexOf() to identify the last occurrence of each element, ensuring each unique value is counted only once: const ...
Read MoreJavaScript Create Submit button for form submission and another button to clear input
Form handling is a fundamental aspect of web development. A Submit button sends the form data for processing, while a Clear button allows users to reset or empty the form inputs. This functionality enhances user experience and ensures proper data entry. In this tutorial, we'll learn how to create a form with a Submit button for handling submissions and a Clear button for resetting inputs using JavaScript. We'll also handle the actions triggered by these buttons effectively. Creating a Submit Button for Form Submission ...
Read MoreMake first letter of a string uppercase in JavaScript?
To make first letter of a string uppercase, use toUpperCase() in JavaScript. With that, we will use charAt(0) since we need to only capitalize the 1st letter. Syntax string.charAt(0).toUpperCase() + string.slice(1) Example function replaceWithTheCapitalLetter(values){ return values.charAt(0).toUpperCase() + values.slice(1); } var word = "javascript" console.log(replaceWithTheCapitalLetter(word)); Javascript Multiple Examples function capitalizeFirst(str) { return str.charAt(0).toUpperCase() + str.slice(1); } console.log(capitalizeFirst("hello world")); console.log(capitalizeFirst("programming")); console.log(capitalizeFirst("a")); console.log(capitalizeFirst("")); Hello world Programming A How It Works The method breaks ...
Read MoreJavaScript undefined Property
The JavaScript undefined property represents a value that indicates a variable has been declared but not assigned a value, or a property that doesn't exist. What is undefined? undefined is a primitive value automatically assigned to variables that are declared but not initialized, and to object properties that don't exist. Common Cases Where undefined Occurs // Declared but not assigned let age; console.log(age); // undefined // Function with no return value function greet() { console.log("Hello"); } let result = greet(); console.log(result); // undefined // Accessing non-existent object property let ...
Read MoreCan we modify built-in object prototypes in JavaScript
Yes, JavaScript allows modifying built-in object prototypes, but it should be done carefully. You can extend native objects like String, Array, or global functions like alert(). What are Built-in Object Prototypes? Built-in object prototypes are the foundation objects that JavaScript provides, such as String.prototype, Array.prototype, and global functions like alert(). Modifying them affects all instances of that type. Example: Overriding the alert() Function Custom Alert Function ...
Read MoreTop n max value from array of object JavaScript
Finding the top n objects with maximum values from an array is a common programming task. Let's explore how to get objects with the highest duration values from an array of objects. Problem Statement Given an array of objects, we need to create a function that returns the top n objects based on the highest duration values. const arr = [ {"id":0, "start":0, "duration":117, "slide":4, "view":0}, {"id":0, "start":0, "duration":12, "slide":1, "view":0}, {"id":0, "start":0, "duration":41, "slide":2, "view":0}, {"id":0, "start":0, "duration":29, "slide":3, ...
Read MoreJavaScript Remove all '+' from array wherein every element is preceded by a + sign
When working with arrays containing strings that start with a '+' sign, you can remove these characters using JavaScript's map() method combined with replace(). Problem Statement Let's say we have an array where every element is preceded by a '+' sign: var studentNames = [ '+John Smith', '+David Miller', '+Carol Taylor', '+John Doe', '+Adam Smith' ]; Using map() with replace() The map() method creates a new array by calling a function on each element. We use replace() to ...
Read MoreDisplay resultant array based on the object's order determined by the first array in JavaScript?
When working with objects and arrays in JavaScript, you often need to reorder data based on a specific sequence. This article shows how to use an array to determine the order of values extracted from an object using the map() method. The Problem Consider an object containing key-value pairs and an array that defines the desired order. We want to create a new array with values from the object, ordered according to the array sequence. // Object with key-value pairs var lastName = { "John": "Smith", "David": "Miller", ...
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