Javascript Articles - Page 312 of 534

Yes, you can use Object.fromEntries() along with substr(). Under substr(), mention the index from where to begin the substring and the length.Exampleconst originalString = {    "John 21 2010" :1010,    "John 24 2012" :1011,    "John 22 2014" :1012,    "John 22 2016" :1013, } const result = Object.fromEntries(Object.entries(originalString). map(([k, objectValue])=> [k.substr(0, k.length-5), objectValue])); console.log(result)To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo41.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo41.js { 'John 21': 1010, 'John 24': 1011, 'John 22': 1013 }

Get data from tag using find() and store that data into array using push(). Let’s say the following is our table − Name Age John23 David26 Let’s fetch the data from and store in an array. Following is the complete code −Example Live Demo Document    .notShown {       display: none;    } Name Age John23 David26    var convertedIntoArray = [];    $("table#details tr").each(function() {       var rowDataArray = ... Read More

Let’s say we have the following string with special character sequence −var fullName=" John Smith ";To separate the above string into substring, use regex and then split(). The syntax is as follows −var anyVariableName=(/\s*\s*/g); var anyVariableName=yourVariableName.trim().split(yourVariableName);Following is the complete JavaScript code −Examplevar fullName=" John Smith "; console.log("The Value="+fullName); var regularExpression=(/\s*\s*/g); var seprateName=fullName.trim().split(regularExpression); console.log(seprateName);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo39.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo39.js The Value= John Smith [ 'John', 'Smith' ]Read More

The easiest way to detect keypresses in JavaScript, use the onKeyPress event handler −document.onkeypressThe key press is matched with the keyCode property, which returns the Unicode character code of the key that triggered the onkeypress event.Example Live Demo Document    document.onkeypress = function (eventKeyName) {       eventKeyName = eventKeyName || window.event;       if(eventKeyName.keyCode==13){          console.log('You have pressed enter key');       } else {          alert(String.fromCharCode(eventKeyName.keyCode))    } }; To run the above program, save the file name ... Read More

To find out which characters key is pressed, use the window.event along with keyCode. Following is the code −Example Live Demo Document    function keyPressName(myEventKeyName){       var pressedKey;       if(window.event){          pressedKey = myEventKeyName.keyCode;       } else if(myEventKeyName.which)       {          pressedKey = myEventKeyName.which;    }    alert(String.fromCharCode(pressedKey)); } 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” ... Read More

To avoid unexpected string concatenation while concatenating strings, multiple strings, and numbers, use backticks.We have the following −const concatValue = 'John, David, Mike'; var friendNames= `${concatValue}`;The above value is concatenated with a string and number −var studentNameWithFriends=` ${concatValue}| 'Carol' | 24 ` ;Following is the complete JavaScript code for concatenation −Exampleconst concatValue = 'John, David, Mike'; var friendNames= `${concatValue}`; var studentNameWithFriends=` ${concatValue}| 'Carol' | 24 ` ; console.log(friendNames); console.log(studentNameWithFriends);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo37.jsOutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo37.js John, David, Mike John, ... Read More

To display only the visible text, use the concept of − visible selector in jQuery. It selects the element currently visible. Following is the code −Example Live Demo Document Test Class Demo class    $('#myDiv').children(":visible").text() 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.This will produce the following output displaying the visible text −

To parse JSON, use parseJSON() and for displaying a specific pair, use the $.each() function.Let’s say the following is our JSON, which is parsed −const APIData = '[{"Name":"John", "Age":21}, {"Name":"David", "Age":24}, {"Name":"Bob", "Age" :20}]'; const getObject = jQuery.parseJSON(APIData);Now, let’s see the complete code and fetch the “Name” pairs −Example Live Demo Document    const APIData =    '[{"Name":"John", "Age":21}, {"Name":"David", "Age":24}, {"Name":"Bob", "Age":20}]';    const getObject = jQuery.parseJSON(APIData);    $.each(getObject, function (k, obj) {       console.log(obj['Name']);    }); To run the above program, save the file name ... Read More

To find all subsets of a set, use reduce() along with map() in JavaScript. Let’s say, we are passing the set [8,9] and finding the subsets.Exampleconst findAllSubsetsoOfGivenSet = originalArrayValue => originalArrayValue.reduce(    (givenSet, setValue) => givenSet.concat(       givenSet.map(givenSet => [setValue,...givenSet])    ), [[]] ); console.log(findAllSubsetsoOfGivenSet([8,9]));To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo36.js.OutputThis will produce the following output.PS C:\Users\Amit\JavaScript-code> node demo36.js [ [], [ 8 ], [ 9 ], [ 9, 8 ] ]

To convert an object into an array, use push() in JavaScript. Following is the code −ExamplestudentDetails=   [       { studentName:"Chris",studentMarks:34},       { studentName:"David",studentMarks:89} ] var convertIntoArray = []; for (var i = 0; i < studentDetails.length; i++) {    convertIntoArray.push(studentDetails[i].studentName); } console.log(convertIntoArray);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo35.js.OutputThis will produce the following output.PS C:\Users\Amit\JavaScript-code> node demo35.js [ 'Chris', 'David' ]