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Object Oriented Programming Articles
Page 381 of 588
How can I get seconds since epoch in JavaScript?
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
Read MoreHow to determine if date is weekend in JavaScript?
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 MoreWhat is the simplest solution to flat a JavaScript array of objects into an object?
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 }
Read MorePossible to split a string with separator after every word in JavaScript
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 MoreLength of a JavaScript associative array?
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==4
Read MoreHow do I subtract one week from this date in JavaScript?
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 MoreJavaScript Update specific index in a boolean matrix?
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 ] ]
Read MoreFunction to create diamond shape given a value in JavaScript?
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
Read MoreReplace a value if null or undefined in JavaScript?
To replace a value if null or undefined, you can use below syntax −var anyVariableName= null; var anyVariableName= yourVariableName|| anyValue;Examplevar value = null; console.log("The value ="+value) var actualValue = value || "This is the Correct Value"; console.log("The value="+actualValue);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo56.jsOutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo56.js The value =null The value=This is the Correct Value
Read MoreJavaScript filter an array of strings, matching case insensitive substring?
Let’s first create array of strings −let studentDetails = [ {studentName: "John Smith"}, {studentName: "john smith"}, {studentName: "Carol Taylor"} ];Now, match case insensitive substring, use the filter() and the concept of toLowerCase() in it. Following is the code −Examplelet studentDetails = [ {studentName: "John Smith"}, {studentName: "john smith"}, {studentName: "Carol Taylor"} ]; var searchName="John Smith" console.log(studentDetails.filter(obj => obj.studentName.toLowerCase().indexOf(searchName.toLowerCase()) >= 0));To run the above program, you need to use the following command;node fileName.js.Here, my file name is demo55.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo55.js [ { studentName: 'John Smith' }, { studentName: ...
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