57. Are functions treated as first class objects in JavaScript? Support your answer with the help of an example in either case.
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Yes, in JavaScript, functions are treated as first-class objects.


A first class function in JavaScript is a function that can be treated as any other data type, such as a string or number. This means that it can be passed around as an argument, returned as a value, and stored in variables.


First class functions are defined by the following characteristics:

  1. Functions can be assigned to variables or constants. For example, let sum = (x, y) => x + y; assigns the function to the variable sum.
  2. Functions can be passed as arguments to other functions. For example, let double = (num, fn) => num * 2; takes a number and a function as arguments and returns the result of calling the function with the doubled number.

  3. Functions can return values that are used by other parts of the program. For example, let factorial = n => n > 1 ? n * factorial(n-1) : 1; returns a value that is used to compute the factorial of a given number.

  4. Functions can be nested within other functions or blocks of code. For example, let map = (arr, fn) => arr.map(fn); takes an array and a function as arguments and returns a new array with the results of calling the function on each element of the original array.

    5. Here are some examples that demonstrate the characteristics of first class functions in JavaScript:

    let sum = (x, y) => x + y; // a first class function assigned to the variable sum
let double = (num, fn) => num * 2; // a function that takes a number and a function as arguments
let factorial = n => n > 1 ? n * factorial(n-1) : 1; // a function that returns a value used to compute the factorial of a number
let map = (arr, fn) => arr.map(fn); // a function that takes an array and a function as arguments
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