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Javascript Articles
Page 276 of 534
Converting array of arrays into an object in JavaScript
Suppose we have an array of arrays that contains the performance of a cricket player like this −const arr = [ ['Name', 'V Kohli'], ['Matches', 13], ['Runs', 590], ['Highest', 183], ['NO', 3], ['SR', 131.5] ];We are required to write a JavaScript function that takes in one such array of arrays. Here, each subarray represents one key-value pair, the first element being the key and the second its value. The function should construct an object based on the key-value pairs in the array and return the object.Therefore, for the above array, the output should look ...
Read MoreConverting object to 2-D array in JavaScript
Suppose we have an object that contains information about the weather of a city −const obj = { city: "New Delhi", maxTemp: 32, minTemp: 21, humidity: 78, aqi: 456, day: 'Tuesday', };We are required to write a JavaScript function that takes in one such object. The function should construct an array of arrays based on this object where each subarray contains exactly two properties −the corresponding keythat key's valueTherefore, for the above object, the output should look like −const output = [ [ 'city', 'New Delhi' ], [ 'maxTemp', 32 ], ...
Read MoreFinding sum of alternative elements of the array in JavaScript
We are required to write a JavaScript function that takes in an array of Numbers as the only argument. The function should calculate and return the sum of alternative elements of the array.For example −If the input array is −const arr = [1, 2, 3, 4, 5, 6, 7];Then the output should be −1 + 3 + 5 + 7 = 16ExampleFollowing is the code −const arr = [1, 2, 3, 4, 5, 6, 7]; const alternativeSum = (arr = []) => { let sum = 0; for(let i = 0; i < arr.length; i++){ const el = arr[i]; if(i % 2 !== 0){ continue; }; sum += el; }; return sum; }; console.log(alternativeSum(arr));OutputFollowing is the output on console −16
Read MoreAwkward behaviour of delete operator on arrays in JavaScript
The delete operator in JavaScript is actually an object operator (used with objects).But since arrays are also indexed objects in JavaScript, we can use the delete operator with arrays as well.Consider the following array of literals −const arr = ['a', 'b', 'c', 'd', 'e'];ExampleLet us now execute the following program and guess the expected output −const arr = ['a', 'b', 'c', 'd', 'e']; delete arr[4]; console.log(arr); console.log(arr.length);OutputThe output of this program in the console will be −[ 'a', 'b', 'c', 'd', ] 5Understanding the output −Since we deleted one index value of the array, we expected the array.length to ...
Read MoreDecimal to binary conversion using recursion in JavaScript
We are required to write a JavaScript function that takes in a number as the first and the only argument. The function should use recursion to construct a string representing the binary notation of that number.For example −f(4) = '100' f(1000) = '1111101000' f(8) = '1000'ExampleFollowing is the code −const decimalToBinary = (num) => { if(num >= 1) { // If num is not divisible by 2 then recursively return proceeding // binary of the num minus 1, 1 is added for the leftover 1 num if (num % 2) ...
Read MoreReversing the order of words of a string in JavaScript
We are required to write a JavaScript function that takes in a string as the only argument.The function should reverse the order of the words in the string and return the new string.The only condition is that we cannot use the inbuilt array method reverse().For example −If the input string is −const str = 'this is a string';Then the output string should be −const str = 'this is a string';ExampleFollowing is the code −const str = 'this is a string'; const reverseWordOrder = (str = '') => { const strArr = str.split(' '); let temp = ''; ...
Read MoreUnique intersection of arrays in JavaScript
We are required to write a JavaScript function that takes in two arrays of numbers, let’s say arr1 and arr2. The function should find the intersection between the elements of the array. i.e., the elements that appear in both the arrays.The only condition is that if we encountered one element before as intersected, we should not consider it again even if appears again in both the arrays.For example −If the input arrays are −const arr1 = [1, 5, 7, 3, 1]; const arr2 = [1, 7, 3, 1, 6];Then the output array should be −const output = [1, 3, 7];However, ...
Read MoreWait for complex page with JavaScript to load using Selenium.
We can wait for a complex page with JavaScript to load with Selenium. After the page is loaded, we can invoke the Javascript method document.readyState and wait till complete is returned.SyntaxJavascriptExecutor js = (JavascriptExecutor)driver; js.executeScript("return document.readyState").toString().equals("complete");Next, we can verify if the page is ready for any action, by using the explicit wait concept in synchronization. We can wait for the expected condition presenceOfElementLocated for the element. We shall implement the entire verification within the try catch block.Exampleimport org.openqa.selenium.By; import org.openqa.selenium.WebDriver; import org.openqa.selenium.WebElement; import org.openqa.selenium.chrome.ChromeDriver; import org.openqa.selenium.support.ui.ExpectedConditions; import org.openqa.selenium.support.ui.WebDriverWait; import org.openqa.selenium.JavascriptExecutor; public class PageLoadWt{ public static void main(String[] args) { ...
Read MoreCapturing JavaScript error in Selenium.
We can capture Javascript error in Selenium. This type of error appears at the Console Tab on opening the Developer tools in the browser. This can occur due to some functional issue in the page or due to extra logs which may cause performance issues.We can handle the Javascript errors with the driver object and manage method.Exampleimport org.openqa.selenium.By; import org.openqa.selenium.WebDriver; import org.openqa.selenium.WebElement; import org.openqa.selenium.chrome.ChromeDriver; import java.util.List; import java.util.ArrayList; import org.openqa.selenium.logging.LogEntries; import org.openqa.selenium.logging.LogEntry; import org.openqa.selenium.logging.LogType; import java.util.logging.Level; import java.util.Set; public class JavascrptLogErs{ public static void main(String[] args) { System.setProperty("webdriver.chrome.driver", "C:\Users\ghs6kor\Desktop\Java\chromedriver.exe"); WebDriver ...
Read MoreSum of all multiples in JavaScript
We are required to write a JavaScript function that takes in a number, say n, as the first argument, and then any number of arguments following that.The idea is to sum all numbers upto n which are divided by any of the numbers specified by second argument and after.For example −If the function is called like this −sumMultiples(15, 2, 3);Then the output should be −const output = 83;Because the numbers are −2, 3, 4, 6, 8, 9, 10, 12, 14, 15ExampleThe code for this will be −const num = 15; const sumMultiple = (num, ...arr) => { const dividesAny ...
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