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Short circuit evaluation basically works with the && and || logical operators. The expressions are evaluated left to right.For && operator − Short circuit evaluation with &&(AND) logical operator means if the first expression evaluates to false then whole expression will be false and the rest of the expressions will not be evaluated.For || operator − Short circuit evaluation with ||(OR) logical operator means if the first expression evaluates to true then the whole expression will be true and the rest of the expressions will not be evaluated.Following is the code for short circuit evaluation in JavaScript −Example Live Demo ... Read More
There are two functions in JavaScript for rounding and truncating numbers: Math.round() and Math.trunc() respectively −Math.round() − = It rounds the decimal number to the nearest integer value.Math.trunc() − = It simply removes the fractional part of the decimal number and converts it to a whole number.Following is the code for rounding and truncating numbers in JavaScript −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result, .sample { font-size: 20px; font-weight: 500; color: blueviolet; ... Read More
Following is the code to parse array of objects inside another object using maps or forEach −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 18px; font-weight: 500; color: rebeccapurple; } Parse array of objects inside object CLICK HERE Click on the above button to parse the json object let json = { storeData: [ { ... Read More
JavaScript supports block scope only for variables that were declared using let or const keyword. Variables declared using var support function scope but not block scope.Following is the code for displaying block scope in JavaScript −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; color: blueviolet; } Block scope JavaScript Click Here Click on the above button to create variables with var and let ... Read More
Following is the code to parse array of objects inside an object using maps or forEach using JavaScript −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 18px; font-weight: 500; color: rebeccapurple; } Parse array of objects inside object CLICK HERE Click on the above button to parse the json object let json = { storeData: [ { ... Read More
The new operator is used for creating a user-defined object type instance of one of the builtin object types that has a constructor function.Following is the code for new operator in JavaScript −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; color: blueviolet; } New Operator in JavaScript Click Here Click on the above button to create the object person1 from Person constructor ... Read More
Following is the code to refer JavaScript function from within itself −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; color: blueviolet; } Referring JavaScript function from within itself Click Here Click on the above button to call the printHello() function let resEle = document.querySelector(".result"); let BtnEle = document.querySelector(".Btn"); function printHello(num) { for (let i = 0; i < num; i++) { resEle.innerHTML += "Hello World "; printHello(--num); } } BtnEle.addEventListener("click", () => { printHello(3); }); OutputOn clicking the ‘Click Here’ button −
Following is the code for binding an object’s method to a click handler in JavaScript −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; color: blueviolet; } Binding an object's method to a click handler in JavaScript Click Here Click on the above button to know how many times you have clicked the button let resEle = document.querySelector(".result"); let BtnEle = document.querySelector(".Btn"); let testObj = { a: 0, timesClicked() { this.a += 1; resEle.innerHTML = "Times clicked = " + this.a; }, }; BtnEle.addEventListener("click", () => { testObj.timesClicked(); }); OutputOn clicking the ‘Click Here’ button −
Following is the code to share a method between objects in an array −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 18px; font-weight: 500; color: rebeccapurple; } Share a method between objects in an array CLICK HERE Click on the above button to call welcome() method of all person objects let resEle = document.querySelector(".result"); function Person(firstName, lastName) { this.firstName = firstName; ... Read More
Following is the code for modifying built-in object prototypes in JavaScript −Example Live Demo Document body { font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif; } .result { font-size: 20px; font-weight: 500; color: blueviolet; } Modify built-in object prototypes Click Here Click on the above button to call the alert method let resEle = document.querySelector(".result"); let BtnEle = document.querySelector(".Btn"); window.alert = function (msg) { resEle.innerHTML = "Custom Alert function has been triggered"; resEle.innerHTML += "Alert Message = " + msg; }; BtnEle.addEventListener("click", () => { alert("Hello World"); }); OutputOn clicking the ‘Click Here’ button −