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Articles by Sravani Alamanda
15 articles
How to use directives in angular 8?
Directives in Angular 8, are classes that can add new behavior to the elements in the template. Directives are used to manipulate the DOM. We can change the behavior and appearance of the DOM elements using directives. Simply we can use the HTML using directives. Using directives, we can achieve reusability, readability and maintainability. Directives will give the high-level of reusability throughout the application. This will help in large application like same functionality required by many places. There are 3 types of directives − Component directives Attribute directives Structural directives We can also create custom directives based on ...
Read MoreHow to use an Anagular 8 Service?
In Angular, services are singleton objects which normally get instantiated only once for the entire angular application. Every service contains several methods and that includes some functionality to do. It is a mechanism to share functionality or responsibility within one or more than components. We know, using angular we can create nested-based components. Once our applications are nested, we may need to use the same functionality. Instead of writing same code in multiple components. We can write one place and we can share data with different components. The best way to use service to handle this. In first versions of ...
Read MoreHow to inject a service into the component in Angular 8?
In Angular, services are singleton objects which normally get instantiated only once for the entire angular application. Every service contains several methods and that includes some functionality to do. It is a mechanism to share functionality or responsibility within one or more than components. We know, using Angular we can create nested-based component. Once our applications are nested, we may need to use the same functionality. Instead of writing same code in multiple components. We can write one place and we can share data with different components. The best way to use service to handle this. In first versions of ...
Read MoreDifference between constructor and ngOnInit in Angular 8
We can create robust applications using a number of life cycle functions using Angular. As it is the response of the event, the constructor and ngOnInit play important roles in developing applications. May this constructor and ngOnInit terms often confuse us. Constructor and ngOnInit will be available from the life cycle hooks of a component. This will provide extensive benefits to us in developing applications. Let’s check the differences below. Before that, let’s discuss the constructor and ngOnInit in detail. What is the Constructor in Angular 8? Constructor is a default method for a class and is called whenever we ...
Read MoreHow to add event listeners in HTML using AngularJS?
In AngularJS, events help us to perform particular tasks, based on the action. AngularJS is rich in events and has a simple model for adding event listeners to the HTML. AngularJS supports many events related to the mouse and keyboard. All these events are applied to the HTML elements. In angularJs, we have many HTML events. Suppose we write both AngularJS and HTML events simultaneously. AngularJS event and HTML event will be executed and AngularJS event will not overwrite the HTML event. Events can be represented by using directives. Like ng-click, ng-change, ng-mousedown, ng-mouseup, ng-keydown, ng-keyup, ng-keypress, ng-mouseover, ng-paste etc. ...
Read MoreHow to catch syntax errors in JavaScript?
In this tutorial, we will learn how to catch syntax errors in JavaScript. In JavaScript, we get will errors if we write any mistakes in code. Like, ReferenceError, i.e., when we call a variable that does not exist in our code. TypeError i.e. when we tried to change the value which is immutable or try to use a variable in an appropriate way. SyntaxError i.e. when we tried to interpret invalid code. We will learn more about this error in detail below. What is Syntax Error? A syntax error is thrown when there is a glitch in ...
Read MoreFind the non-digit character with JavaScript Regular Expression
In this tutorial, we will learn to find the non-digit character with JavaScript regular expression. ASCII code 'A' is 65 and 'a' is 97 etc. Now, we will check how to find a nondigit element (\D) in a given text using RegExp. RegExp is an object that specifies the pattern used to do search and replace operations on string or for input validation. RegExp was introduced in ES1 and it is fully supported by all browsers. Syntax Syntax for the non-digit element is, new RegExp("\D") or simply /\D/ /\D/, is introduced in ES1. It is fully supported by ...
Read MoreHow to catch any JavaScript exception in Clojurescript?
In our code, usually, we will get an issue with errors. Errors will disturb the normal flow of our application. So, it is required to handle error exceptions in our code to implement any application in any programming language. Now, we will see how to handle exceptions in Clojurescript. Before that, first we learn what Clojurescript is. What is ClojureScript? At the fundamental level, Closurescript is an accent of the closure programming language that is used to compile to JavaScript. Actually, closure originally compiled only to Java virtual machine bytecode, later in 2011 Closurescript came as an option to ...
Read MoreCalculate text width with JavaScript
To calculate text width, we can use the measureText() method in JavaScript. In canvas, the measureText() method is used to measure width of the text content. This means we can pass text to this canvas method and then call that method to measure the text. It will return an object that contains information about the measured text. Sometimes, width may be a float value; hence the Math.ceil() method is used to round the value and returns an integer. Syntax Following is the syntax of the method used to calculate the text width - const text = "Hello World!"; ...
Read MoreHow -Infinity is converted to String in JavaScript?
We all know that string is one of the primitive data types in JavaScript. JavaScript allows us to do some operations on strings like finding characters in the string, changing all characters into lowercase or into uppercase, concatenating with other strings, replacing with other strings, searching character(s) or word(s) from string, etc. We denote string in single quotations or in double quotations. typeof string variable will be a string. Syntax Syntax for String() method is, like String(value) value is required. value is JavaScript value. String() method returns a value i.e. as a string. String() method introduced ...
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