For this, you can use find() along with a map(). Let’s say we have student records with name, rollno and subject.Examplevar firstObject= [    { "FirstName": "David", "RollNo": "105", "Subject": "MongoDB" },    { "FirstName": "Mike", "RollNo": "110", "Subject": "JavaScript"} ]; var secondObject= [    { "FirstName": "Bob", "RollNo": "101", "Subject": "Java" },    { "FirstName": "John", "RollNo": "110", "Subject": "MySQL" } ]; var output = firstObject.map(first=>(secondObject.find(second=>second.RollNo==first.R ollNo) || first)); console.log(output);To run the above program, you need to use the following command −node fileName.jsHere, my file name is demo33.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo33.js [   ... Read More

To separate the special character, use the concept of match() with Regular Expression. The syntax is as follows −yourStringName.flatMap(anyVariableName => yourVariableName.match(/\w+|\W+/g));Let’s say, the following is our array with special characters in between values −var allNames = ['John-Smith', 'David', 'Carol%Taylor'];Let’s now see how to separate text with special characters. Following is the code −Examplevar allNames = ['John-Smith', 'David', 'Carol%Taylor']; var output = allNames.flatMap(obj => obj.match(/\w+|\W+/g)); console.log(output);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo32.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo32.js [    'John', '-',    'Smith', 'David',   ... Read More

To extract the value of the , use −document.getElementById(“yourTextIdValue”).textContentExample Live Demo Document This is the JavaScript....    var originalText = document.getElementById("myText").textContent;    console.log(originalText); To run the above program, just save the file name anyName.html(index.html) and right click on the file and select the option open with live server in VS Code editor.OutputThis will produce the following output display the value −

Setting object values to null can help reset data, free up memory, or show that a value is no longer needed. In JavaScript, the null value is used to indicate that there is an intentional absence of any object value. This article provides various methods for setting JavaScript object values to null and what that means. Setting an Object's values to null Setting object values to null can be done in two types: For Specific Object Value For Multiple Object Value For Specific Object Value Setting the specific ... Read More

Let’s say we have the following strings. One of them is beginning with a question mark i.e. punctuation −var sentence1 = 'My Name is John Smith.' var sentence2 = '? My Name is John Smith.'We need to check whether any of the above two sentences begin with punctuation. To check if string begins with punctuation, the code is as follows −Examplevar punctuationDetailsRegularExpression=/^[., :!?]/ var sentence1 = 'My Name is John Smith.' var output1 = !!sentence1.match(punctuationDetailsRegularExpression) if(output1==true)    console.log("This ("+sentence1+") starts with a punctuation"); else    console.log("This ("+sentence1+") does not starts with a punctuation"); var sentence2 = '? My Name is ... Read More

Let’s say the following is our string with whitespace −var fullName=" John Smith ";Use replace() and set Regex in it to remove whitespaces.Examplefunction removeSpacesAtTheBeginningAndTheEnd(name) {    return name.toString().replace(/^\s+|\s+$/g,''); } var fullName=" John Smith "; var valueAfterRemovingSpace=removeSpacesAtTheBeginningAndTheEnd(fullName) console.log(valueAfterRemovingSpace);To run the above program, you need to use the following command −node fileName.js.Here my file name is demo208.js.OutputThis will produce the following output −PS C:\Users\Amit\javascript-code> node demo208.js John Smith

Let’s say the following is our array −var numbers = [10, 3, 40, 50, 20, 30, 100]We need to search two numbers from the above array elements, whose sum is 80.For this, use simple for loop with if condition.Examplefunction specificPairsOfSumOfTwoNumbers(numbers, totalValue)    {       var storeTwoNumbersObject = {}       for(var currentNumber of numbers)       {          if(storeTwoNumbersObject[currentNumber])          {             return {                firstNumber: totalValue-currentNumber, secondNumber:currentNumber}             }         ... Read More

Let’s say the following is our JSON array −var details = [    {       "customerDetails": [             {                "customerName": "John Smith",                "customerCountryName": "US"             }       ]    },    {       "customerDetails": [          {             "customerName": "David Miller",             "customerCountryName": "AUS"          }       ]    },    { ... Read More

To make addEventListener() repeatedly work on button clicks, use the following code −Example Live Demo Document Click Me    var eventValue = function (event) {       document.body.appendChild(document.createElement('div'))       .textContent = event.type;    }    var pressed = document.querySelector("#pressButtonDemo");    pressed.addEventListener("click", eventValue); To run the above program, save the file name “anyName.html(index.html)” and right click on the file. Select the option “Open with Live Server” in VS Code editor.OutputThis will produce the following output −When you click the button “Click Me” then you will get ... Read More

Let’s say the following is our array with elements preceded by a + sign −var studentNames = [    '+John Smith',    '+David Miller',    '+Carol Taylor',    '+John Doe',    '+Adam Smith' ];To remove the + sign, the code is as follows −ExamplestudentNames = [    '+John Smith',    '+David Miller',    '+Carol Taylor',    '+John Doe',    '+Adam Smith' ]; console.log("The actual array="); console.log(studentNames); studentNames = studentNames.map(function (value) {    return value.replace('+', ''); }); console.log("After removing the + symbol, The result is="); console.log(studentNames);To run the above program, you need to use the following command −node fileName.js.Here my file ... Read More