JavaScript

To check if a string is empty/undefined/null in JavaScript, you can use the “! operator” that returns true for empty strings, undefined values, null values, and other false values. Example 1 function isEmpty(str) { return !str; } const emptyString = ”; const nullValue = null; const undefinedValue = undefined; const nonEmptyString = ‘Hello, world!’; console.log(isEmpty(emptyString)); console.log(isEmpty(nullValue)); … Read more

JavaScript eval() is a built-in function that “evaluates or executes an argument”. The function accepts a string as an argument, evaluates it as an expression, and returns the result. Syntax eval(string) Arguments string: It takes a string which is a  JavaScript expression, variable, statement, or sequence of statements. Return value The eval() function returns the result … Read more

To count elements of an array in JavaScript, you can use the “length” property. The “length” property sets or returns the number of elements in an array. The value of a length property is the integer with a positive sign and a value less than 2 to the 32nd power. Syntax array.length To set the … Read more

To perform integer division by first doing “regular division” and then using “Math.floor()”, “Math.trunc()”, or “bitwise operator” to discard the decimal part of the result. In JavaScript, there is no built-in operator or function precisely for integer division. Method 1: Using the Math.floor() function The “Math.floor()” method “rounds down a number to the nearest integer”. … Read more

In JavaScript, default parameters are used when a value for a given parameter is not provided or is “undefined”. This feature was introduced in ECMAScript 2015 (ES6) and allows for more concise and readable code. Syntax function functionName(parameter1 = defaultValue1, parameter2 = defaultValue2, …) { // function body } How to set default parameters in … Read more

To set a time delay in JavaScript, you can use the “setTimeout()” function. The “setTimeout()” function allows you to execute a function or code after a specified delay. Syntax setTimeout(functionToExecute, delayInMilliseconds, arg1, arg2, …); Parameters functionToExecute: The function you want to execute after the specified delay. delayInMilliseconds: The delay in milliseconds before the function is … Read more

To check if a function exists in JavaScript, you can use the “typeof” operator. Example 1 function mainFunction() { console.log(‘Hello, world!’); } if (typeof mainFunction === ‘function’) { mainFunction(); // Calls the function if it exists } else { console.log(‘The function does not exist.’); } Output In this example, typeof mainFunction will return the string … Read more

There are five different ways to copy an Object in JavaScript. Using the “Object.assign()” method Using the “Spread operator” Using the “JSON.parse()” and “JSON.stringify()” methods Using the “Object.create()” method Deep copy using a “custom function”. Method 1: Using the Object.assign() method Object.assign() copies the values of all enumerable properties from one or more source objects to a target … Read more

To convert CSV to Array in JavaScript, you can use the “string.split()” method. The split() is a built-in String function that splits a provided string into an array of strings by separating it into substrings using a separator provided in the argument. Syntax string.split(separator, limit) Parameters Arguments Value separator The separator argument is used to specify … Read more