Javascript Articles - Page 379 of 534

The Lodash library is in JavaScript, which works on the top of ‘_.js’. It can be used while working with arrays, strings, objects, numbers, etc. The assign() method This function is used to copy the original object into a new object. The difference in this and the spread operator is when nested objects are present and if assign() is used to copy the object, then the nested object will not change and the other variables of the object can be changed. There are two parameters to the assign() function. The first parameter is curly braces {} which is used to ... Read More

The only hard dependency(without which backbone js won't work at all) is Underscore.js. Underscore is a JavaScript library that provides a whole mess of useful functional programming helpers without extending any built-in objects.There are other dependencies required as you proceed to use more advanced features of backbone.js. For example,Libraries for RESTful persistence(Backbone.sync)History support via Backbone.RouterDOM manipulation with Backbone.View or Jquery

The Stack property in JavaScript is used to store and keep track of the errors and saves the information such as the type of the error, where the error is raised and the reason of the error. The path of the origin of the error is also stored in the stacks in JavaScript. Stack is the error class property in JavaScript, which is also used to store the functions that are called, the order of the functions called too. The format of the error shown is as first, in the first line the type of the error will be displayed ... Read More

The parseInt function available in JavaScript has the following signature −parseInt(string, radix);Where the parameters are the following −string − The value to parse. If this argument is not a string, then it is converted to one using the ToString method. Leading whitespace in this argument is ignored.radix − An integer between 2 and 36 that represents the radix (the base in mathematical numeral systems) of the string.If the radix parameter is omitted, JavaScript assumes the following −If the string begins with "0x", the radix is 16 (hexadecimal)If the string begins with "0", the radix is 8 (octal). This feature is ... Read More

Both new Object() notation and Object literal({}) notations do the same thing. They initialize an object. However, the second notation can be a little different if you start adding properties to it.Examplelet a = {    name: 'Ayush' }This initialization is equivalent to −let a = new Object(); a.name = 'Ayush'orlet a = {} a.name = 'Ayush'

JavaScript programming language that is usually used for web scripting. It is a lightweight, interpreted programming language. JavaScript is one of the most programming languages for web development. For running JavaScript each browser has its own engine which enables the proper functioning of JavaScript in the browser. Some common Browsers and their JavaScript engines are −Spider Monkey for firefoxV8 for Google ChromeJavaScript code for SafariChakra for Microsoft Internet Explorer/ edgeTo make JavaScript universe and stop a browser from describing their own scripts. There is a standard set for JavaScript which will be used throughout the browser. there is an Association ... Read More

To convert, use JSON.stringify(). Following is the code to convert MySQL DATETIME value to JSON format in JavaScript − var mySQLDateTime = new Date("Fri Sep 06 2019 22 −54 −48 "); var yearValue = mySQLDateTime.getFullYear(); var dateValue = mySQLDateTime.getDate(); var monthValue=mySQLDateTime.getMonth(); var hour=mySQLDateTime.getHours(); var minutes=mySQLDateTime.getMinutes(); var second=mySQLDateTime.getSeconds(); jsonObject={"year" −yearValue,"month" :monthValue,"DateValue" :dateValue,"Hour" :hour ,"Minutes" :minutes,"Second" :second}; var dateJsonObject = JSON.stringify(jsonObject); document.write(dateJsonObject); The screenshot of the code is as follows −This will produce the following output −{"year" :2019,"month" :8,"DateValue" :6,"Hour" :22,"Minutes" :54,"Second" :48}The snapshot of the output is as follows −

Regardless of the programming language, memory life cycle is pretty much always the same −Allocate the memory you needUse the allocated memory (read, write)Release the allocated memory when it is not needed anymoreThe second part is explicit in all languages. Use of allocated memory needs to be done by the developer.The first and last parts are explicit in low-level languages like C but are mostly implicit in high-level languages like JavaScript.Hence there is no explicit way to allocate or free up memory in JavaScript. Just initializing objects allocates memory for them. When the variable goes out of scope, it is ... Read More

In the JavaScript, Event Flow process is completed by three concepts −Event Target − The actual DOM object on which the event occured.Event Bubbling − Explained belowEvent Capturing − Explained belowEvent bubbling is the order in which event handlers are called when one element is nested inside a second element, and both elements have registered a listener for the same event (a click, for example). With bubbling, the event is first captured and handled by the innermost element and then propagated to outer elements.With capturing, the event is first captured by the outermost element and propagated to the inner elements.Let's ... Read More

JavaScript has two values for nothing i.e., null and undefined. These two are also the primitive types in JavaScript. Undefined Out of the two values, Undefined in JavaScript means if a variable is declared and no value is assigned to the variable, then this variable is said to be undefined. An object can also be null. It is said to be null when there is no value to it. Example 1 This example of the undefined value in JavaScript. var str console.log('The value of given variable is:', str) In the above example 1, a variable named ‘str’ is declared. ... Read More