To get seconds since epoch, use the below syntax −var anyVariableName= new Date(); Math.round(yourDateVariableName.getTime() / 1000);At first, get the current date −var currentDate= new Date();Now, get seconds since epoch −Examplevar currentDate= new Date(); var epochSeconds = Math.round(currentDate.getTime() / 1000); console.log(epochSeconds);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo67.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo67.js 1594821507

As we know the value 0 is for day Sunday and 6 for Saturday. First of all, you need to get day with the help of getDay().Let’s set a date −var givenDate=new Date("2020-07-18");Now, we will get the day −var currentDay = givenDate.getDay();Following is the code to determine if date is weekend −Examplevar givenDate=new Date("2020-07-18"); var currentDay = givenDate.getDay(); var dateIsInWeekend = (currentDay === 6) || (currentDay === 0); if(dateIsInWeekend==true){    console.log("The given date "+givenDate+" is a Weekend"); } else {    console.log("The given date " +givenDate+"is a not a Weekend"); }To run the above program, you need to use the ... Read More

In this article, using the filter() and includes() methods in JavaScript, we can filter an array based on the elements presence in another array or specific conditions. For suppose we have two arrays as array1 and array2. we want to filter array1 to include only the elements that are present in array2. To have the clear idea about the filter() and includes() in JavaScript. Let's discuss individually. JavaScript filter() and includes() Methods filter(): It is used to create a new array that includes only the elements that satisfy the condition provided by the callback function. includes(): Using includes(), the callback ... Read More

Flat array of objects into an object, you can use the concept of reduce(). Let’s say following is our array of objects −const studentDetails = [    {Name: "Chris"},    {Age: 22} ]Exampleconst studentDetails = [    {Name: "Chris"},    {Age: 22} ] const objectStudent = studentDetails.reduce((obj, value) => {    return { ...obj, ...value } }, {}) console.log(objectStudent);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo64.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo64.js { Name: 'Chris', Age: 22 }

To split a string with separator after every word, the syntax is as follows −var anyVariableName=yourVariableName.split('parameter').filter(value=>value)Let’s say, the following is our string with separator −var sentence="-My-Name-is-John-Smith-I-live-in-US";Now, split the string with separator as in the below code.Examplevar sentence="-My-Name-is-John-Smith-I-live-in-US"; console.log("The value="+sentence); var result=sentence.split('-').filter(value=>value) console.log("After split()="); console.log(result);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo63.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo63.js The value=-My-Name-is-John-Smith-I-live-in-US After split()= [    'My', 'Name',    'is', 'John',    'Smith', 'I',    'live', 'in',    'US' ]Read More

You can use the length property from JavaScript to get the length. Let’s create an Associative array −var details = new Array(); details["Name"] = "John"; details["Age"] = 21; details["CountryName"] = "US"; details["SubjectName"] = "JavaScript";Let us now get the length of the associative array −Examplevar details = new Array(); details["Name"] = "John"; details["Age"] = 21; details["CountryName"] = "US"; details["SubjectName"] = "JavaScript"; console.log("The length=="+Object.keys(details).length);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo.js The length==4Read More

To convert HH:MM:SS to seconds with JavaScript, we will be using simple arithmetic operations like mltiplication and addition. We will be understanding this conversion with two example codes and their stepwise explanation. In this article, we are given a time in HH:MM:SS format and our task is to convert HH:MM:SS to seconds with JavaScript. Steps to Convert HH:MM:SS to Seconds We have used two div to display the time and the result in seconds. The time variable stores the time in HH:MM:SS format. Then we have used split() function to ... Read More

You need to subtract one week i.e. 7 days from the current date. Following is the syntax −var anyVariableName=new Date(yourCurrentDate.setDate(yourCurrentDate.getDate() - 7)At first, get the current date −var currentDate = new Date(); console.log("The current Date="+currentDate);Now, set the new date with setDate() method and subtract 7 days −Examplevar currentDate = new Date(); console.log("The current Date="+currentDate); var before7Daysdate=new Date(currentDate.setDate(currentDate.getDate() - 7)); console.log("The One week ago date="+before7Daysdate);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo60.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo60.js The current Date=Tue Jul 14 2020 19:12:43 GMT+0530 (India ... Read More

To updates, use the concept of fill() in JavaScript. The fill() method is used to fill the array elements with a static value. Following is the code −Exampleconst array= Array(4) var fillWithTrueValue=array.fill(true); const matrixWithOnlyBooleanTrue = Array(4).fill(fillWithTrueValue); console.log(matrixWithOnlyBooleanTrue);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo59.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo59.js [    [ true, true, true, true ],    [ true, true, true, true ],    [ true, true, true, true ],    [ true, true, true, true ] ]

You can create your own function to create diamond shapes for a given value. Following is the code −Examplefunction createDimondShape(size){    for(var i=1;i=i;s--){          process.stdout.write(" ");       }       for(var j=1;j