Front End Technology Articles - Page 576 of 860

_isEqual() _isEqual() is from the underscore and lodash library of javascript. It is used to compare javascript objects. The importance of this method is that it doesn't care about the order of properties while comparing the objects. It only checks whether the properties in the two objects are equal or not. Whereas JSON.stringify(), which is used in comparing the objects, checks even the order of properties of the objects, making _isEqual() the better option. syntax_.isEqual(object1, object2);It accepts two objects as parameters and scrutinizes whether they are equal or not.ExampleLive Demo    var obj1 = {name: "Sikha", designation: "Content developer"}; ... Read More

Objects in JavaScript is an entity, where it consists of properties and type. Let’s consider sports as an object, in Car the properties can be color, price, height, width, etc. Exactly the same also happens in JavaScript, which has objects and contains properties to them. Const car = { color : 'Black', price : 2500000, height : '6 feet', width : '5 feet' } The equality operator (===) verifies whether the two operands are equal or not and returns a Boolean value. If the both operands are ... Read More

In this article, we are going to discuss how to use the spread operator to clone an array in JavaScript. Cloning is just the process of copying one array into another array. Previously, the slice() method was used to clone an array, however, ES6 now provides the spread operator(...) to simply clone an array. Before proceeding further let us look at the definitions of array and spread operator. Array An Array is usually a data structure, in JavaScript it is an object which can hold multiple values at once. For example, Below “Arr” is an array. Const Arr = [‘Tutorials’, ... Read More

We can define a property of an object using Dot and Bracket notations. There is also another way in which a property called Object.defineProperty() is used to define a property. It usually takes 3 parameters they are object name, property name, property descriptor.syntaxObject.defineProperty(object name, property name, property descriptor)Lets' define a property with this method.ExampleIn the following example, initially, the object has only one property named 'one'. Later on, another property named 'two' is added. Now when we tried to display all the properties, only the first property was displayed but not the added property as shown in the output.Live Demo   ... Read More

The length property is only applicable to arrays and strings. So when we call the length property on an object we will get undefined.ExampleLive Demo    var object = {prop:1, prop:2};    document.write(object.length); OutputundefinedWhereas arrays and strings will display their length when length property is used on them.ExampleLive Demo    var string = 'hello';    var array = [1, 2, 3];    var len1 = string.length;    var len2 = array.length;    document.write(len1);    document.write("");    document.write(len2); Output5 3In javascript, we have Object.keys() property, which checks whether there are any properties or not. If we use the length property ... Read More

focus()Javascript focus() methods helps to highlight a HTML form element. It sets the element as an active element in the current document. In current documentation, focus can be applied to only one single element. The focus can be applied either to a text, a button, etc.  syntaxelement.focus(options);ExampleIn the following example, initially, the text "Tutorialspoint" is in an anchor tag 'a', which as an id called 'focus'. Later on, a function is declared in which the id is called using a DOM method and focus() method is applied on it to change the color of text "Tutorialspoint" to red. Here a button ... Read More

Radio button A radio button is used to select one among many options. This is one of the element in HTML. This radio button is a radio group to show a set of multiple choices, and in that only one can be selected. This way far similar to checkboxes, in checkboxes scenario’s we can select either one or many options as we can, whereas in radio button it can’t be done selecting multiple choices. We can define radio button is HTML using tag. Following is the syntax to define radio buttons in HTML Example 1 None selected ... Read More

GeneratorsJavaScript supports Generator functions and Generator Objects. A generator function is the same as a normal function, but whenever it needs to generate a value it uses the 'yield' keyword rather than 'return'. The 'yield' keyword halts the function execution and sends a value back to the caller. It has an ability that it can resume the functionality from where it is left off. syntaxfunction* generator(){ yeild 1; yeild 2; }ExampleIn the following example, using a generator function, natural numbers 10, 9 and 8 were printed. Instead of printing each number individually we can run ... Read More

Math.trunc()Unlike Math.floor(), Math.ceil() and Math.round(), Math.trunc() method removes fractional part and gives out only integer part. It doesn't care about rounding the number to the nearest integer. It doesn't even notice whether the value is positive or negative. Its function is only to chop up the fractional part.syntaxMath.trunc(x);parameters - Math.trunc() takes a number as an argument and truncates the fractional part.In the following example, Math.trunc() method truncated the fractional values of the provided positive numbers.ExampleLive Demo var val1 = Math.trunc("1.414"); var val2 = Math.trunc("0.49"); var val3 = Math.trunc("8.9"); document.write(val1); ... Read More

Floating point A number which is either positive or negative whole number with having a decimal point to it is called floating point. Let’s consider these numbers, 1.52, 0.14 and also -98.345 are considered as floating point numbers. Whereas 77, 56, 90 and 0 are not considered as floating point numbers. In JavaScript this format will store the numbers in 64 bits. The numbers which are in fraction are stored in 0 to 51 bits. Coming to exponent, they are stored in 52 to 62 bits. And the sign bits will be stored in 63rd bit. Floating point arithmetic Floating ... Read More