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Let us first create a nested object −var details = { "teacherDetails": { "teacherName": ["John", "David"] }, "subjectDetails": { "subjectName": ["MongoDB", "Java"] } }Let us now extract the keys. Following is the code −Examplevar details = { "teacherDetails": { "teacherName": ["John", "David"] }, "subjectDetails": { "subjectName": ["MongoDB", "Java"] } } var objectName, nestedObject; var name = "Java"; for(var key in details){ for(var secondKey in details[key]){ if(details[key][secondKey].includes(name)){ objectName = ... Read More
To set sleep i.e. delay, use the concept of setTimeout(). It takes values in milliseconds i.e.1000 milliseconds = 1 second 2000 milliseconds = 2 seconds, etc.For our example, we will add two values with a delay of 5 seconds i.e. 5000 milliseconds. Following is the code −Examplevar firstValue=10; var secondValue=20; var result=firstValue+secondValue; setTimeout(function() { }, (5 * 1000)); console.log("The result="+result);The above setTimeout() will sleep for 5 seconds. To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo95.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo95.js The result=30Read More
To get largest numbers passed using reduce(), use the Math.max() function. Following is the code −const getBiggestNumberFromArraysPassed = allArrays => allArrays.reduce( (maxValue, maxCurrent) => maxValue.push(Math.max(...maxCurrent)),maxValue),[]); console.log(getBiggestNumberFromArraysPassed([[45,78,3,1],[50,34,90,89],[32,10,90,99]]));To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo94.jsOutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo94.js [ 78, 90, 99 ]
Let’s say the following are our two strings −var originalName = "JOHNDOE"; var removalName = "JOHN"We need to remove the second string from first. For this, use replace() along with reduce().Exampleconst removeCharactersFromAString= (removalName,originalName)=>removalName.split('').reduce((obj,v)=>obj.replace(v,''),originalName); var originalName = "JOHNDOE"; var removalName = "JOHN" console.log(removeCharactersFromAString(removalName,originalName));To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo93.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo93.js DOE
To un-nest array of objects, use the concept of map(). Let’s say the following are our array of objects −const studentDetails = [ { "studentId": 101, "studentName": "John", "subjectDetails": { "subjectName": "JavaScript" } }, { "studentId": 102, "studentName": "David", "subjectDetails": { "subjectName": "MongoDB" } } ];We need to un-nest the subjectName and display the result. Following is the code −Exampleconst studentDetails = [ ... Read More
To fetch the highest value, use the Math.max() from JavaScript. Since, we want the one with maximum value, use the Object.values.Exampleconst studentMarksDetails= { marks1:78, marks2:69, marks3:79, marks4:74 } const maximumMarks = Math.max(...Object.values(studentMarksDetails)); console.log("The highest marks="+maximumMarks); for (const key of Object.keys(studentMarksDetails)){ if (studentMarksDetails[key] == maximumMarks) { console.log(`The Object='${key}'`); break; } }To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo91.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo91.js The highest marks=79 The Object='marks3'Read More
To remove extra spaces, you need to use trim() along with regular expressions. Following is our string with spaces before applying trim() −var sentence="My name is John Smith ";Now, we will remove the extra spaces as in the below code −Examplevar sentence="My name is John Smith "; console.log("The actual value="); console.log(sentence); var originalSentence = sentence.replace(/\s+/g, '').trim(); var afterRemovingTheSpace=originalSentence.trim(); console.log("After removing the spaces="); console.log(afterRemovingTheSpace);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo90.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo90.js The actual value= My name is John Smith After removing ... Read More
In order to modify the key values, you need to use regular expressions along with Object.fromEntries().Examplevar underscoreSpecifyFormat = str => str.replace(/(_)(.)/g, (_, __, v) => v.toUpperCase()), JsonObject = { first_Name_Field: 'John', last_Name_Field: 'Smith'}, output = Object.fromEntries(Object.entries(JsonObject).map(([key, value]) => [underscoreSpecifyFormat(key), value])); console.log("The JSON Object="); console.log(output);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo89.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo89.js The JSON Object= { firstNameField: 'John', lastNameField: 'Smith' }
To remove ‘0’. ‘undefined’ and empty values, you need to use the concept of splice(). Let’s say the following is our array −var allValues = [10, false, 100, 150 ,'', undefined, 450, null]Following is the complete code using for loop and splice() −Examplevar allValues = [10, false, 100, 150 ,'', undefined, 450, null] console.log("Actual Array="); console.log(allValues); for (var index = 0; index < allValues.length; index++) { if (!allValues[index]) { allValues.splice(index, 1); index--; } } console.log("After removing false, undefined, null or ''..etc="); console.log(allValues);To run the above program, you need to use the following ... Read More
Let’s say the following is our start value −var startValue=10;Let’s say the following is our end value −var endValue=20;Use the for loop to fetch numbers between the start and end value −Examplevar startValue=10; var endValue=20; var total=''; function printAllValues(startValue, endValue){ for(var start=startValue;start < endValue ;start++){ total=total+start+", "; } } printAllValues(startValue, endValue) var allSequences = total.slice(0, -1); console.log(allSequences);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo87.js.OutputThis will produce the following output −PS C:\Users\Amit\JavaScript-code> node demo87.js 10, 11, 12, 13, 14, 15, 16, 17, 18, 19Read More