The conscise arrow function syntax is as follows −(param1, param2) =>param1+param2It doesn’t have the function keyword and the function body. There is only => between the parameters and function body and if there is single parameter than it can also be written like this −param1=>param1*2It has implicit return if there aren’t curly braces {} after the =>.Following is the code to implement concise arrow functions in JavaScript −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .result {       font-size: 20px;     ... Read More

The fat arrow function syntax looks like the following −(param1, param2, ..)=>{ }It doesn’t have the function keyword and only have the => between the parameters and the function body.Following is the code implementing fat arrow functions 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;    } Fat arrow functions CLICK HERE Click on the above button to call the add() fat ... Read More

Following is the code for passing parameters to callback functions 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;    } Passing parameters to callback functions CLICK HERE Click on the above button to pass parameter to callback function add2 and call it    let resEle = document.querySelector(".result");    function add2(a) {       return a + 2;    }    function multiply9(fn, num) {       return fn(num) * 9;    }    document.querySelector(".Btn").addEventListener("click", () => {       resEle.innerHTML = "The number returned = " + multiply9(add2, 8);    }); OutputOn clicking the ‘CLICK HERE’ button −

To empty an array in JavaScript, there are four ways −Setting to new Array − In this we set our array variable to a new empty array.Using length property − In this we set the length property of our array to 0.Using pop − In this we continuously pop the array elements till the length reaches to 0.Using splice − In this we put the start index as 0 and the no of elements to removed as array.length-1.Following is the code to display no. of ways to empty an array in JavaScript −Example Live Demo Document ... Read More

Following is the code to implement asynchronous loop 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;    } Asynchronous loop in JavaScript CLICK HERE Click on the above button to start our asynchronous loop    let resEle = document.querySelector(".result");    async function waitTime(time) {       return new Promise((resolve) => {          setTimeout(resolve, time);       });    }    async function someFunction() {       for (let i = 0; i < 10; i++) {          await waitTime(2000);          resEle.innerHTML += "i = " + i + "";       }    }    document.querySelector(".Btn").addEventListener("click", () => {       someFunction();    }); OutputOn clicking the ‘CLICK HERE’ button the loop will print 1 to 10 −

The best way to add an event to any element is to use the addEventListener() method.Following is the code to add an event in JavaScript −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .result{       font-size: 20px;       font-weight: 500;       color: rebeccapurple;    } Adding event in JavaScript CLICK HERE Click on the above button to increment the font size of above text    let resEle = document.querySelector(".result");    document.querySelector(".Btn").addEventListener("click", () => {       resEle.style.fontSize = "34px";    }); OutputThe above code will produce the following output −On clicking the ‘CLICK HERE’ button −

Following is the code to decrement a date by 1 day 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: rebeccapurple;    } JavaScript program to decrement a date by 1 day Decrement Click on the above button to decrement the date by one day    let resEle = document.querySelector(".result");    let sampleEle = document.querySelector(".sample");    let date = new Date();    sampleEle.innerHTML = date;    document.querySelector(".Btn").addEventListener("click", () => {       date.setDate(date.getDate() - 1);       resEle.innerHTML = "New Date = " + date;    }); OutputThe above code will produce the following output −On clicking the ‘Decrement’ button −

Following is the code for finding keys of a hash in JavaScript −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .result {       font-size: 20px;       font-weight: 500;    } Find keys of a hash in JavaScript DISPLAY Click on the above button to display the hash keys    let resEle = document.querySelector(".result");    let obj = {       firstName: "Rohan",       lastName: "Sharma",       age: 22,    };    document.querySelector(".Btn").addEventListener("click", () => {       resEle.innerHTML += "object keys are " + Object.keys(obj);    }); OutputThe above code will produce the following output −On clicking the ‘DISPLAY’ button −

Following is the code to to display name to be only numbers, letters and underscore using regex in JavaScript −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .result {       font-size: 20px;       font-weight: 500;    } , letters and underscore only regex match

Following is the code to validate decimal numbers in JavaScript −Example Live Demo Document    body {       font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;    }    .result {       font-size: 20px;       font-weight: 500;    } Validate decimal numbers in JavaScript CHECK Click the above button to check if a valid decimal number is entered or not    let resEle = document.querySelector(".result");    document.querySelector(".Btn").addEventListener("click", () => {       var str = document.querySelector(".num").value;       var regex = /^[-+]?[0-9]+\.[0-9]+$/;   ... Read More