--description--

A factorial is the product of an integer and all the integers below it. For example, the factorial of 5 is 5 * 4 * 3 * 2 * 1 = 120. In this lab, you will create a factorial calculator that takes a number from the user and calculates the factorial of that number.

Objective: Fulfill the user stories below and get all the tests to pass to complete the lab.

User Stories:

1. You should declare a variable num and assign it a number of your choice. The assigned number should be between 1 and 20 inclusive.
2. Create a function named factorialCalculator that takes a number as an argument and returns the factorial of that number.
3. Inside the function, declare a result variable and assign it the value of 1. Using a loop, loop through all numbers from 1 to the input number(inclusive) and for each number, multiply the result variable by the current number and assign the result to the result variable. You can choose to use either a for loop, while loop or do...while loop here.
4. You should call the factorialCalculator function with num as the argument and assign the result to the variable factorial.
5. You should store the final output in the format Factorial of [num] is [factorial] and assign it to the variable resultMsg.
6. You should output the value of resultMsg to the console.

--hints--

You should have a num variable.

assert.isDefined(num);

You should assign a value to the num variable

assert.isNotNull(num);

The value of num should be between 1 and 20.

assert.isAtLeast(num, 1);
assert.isAtMost(num, 20);

The num value should be a number.

assert.isNumber(num);

You should have a function named factorialCalculator.

assert.isFunction(factorialCalculator);

The factorialCalculator function should take a number as an argument.

assert.match(factorialCalculator.toString(), /\s*factorialCalculator\(\s*\w+\s*\)/);

The factorial of 5 should return 120.

assert.strictEqual(factorialCalculator(5), 120);

The factorial of 7 should return 5040.

assert.strictEqual(factorialCalculator(7), 5040);

You should call your factorialCalculator function with the num variable as the argument.

assert.match(__helpers.removeJSComments(code), /factorialCalculator\(\s*num\s*\)\s*;?\s*$/m);

You should define a factorial variable and assign the result of the factorialCalculator function to it.

assert.isDefined(factorial);
assert.strictEqual(factorial, factorialCalculator(num));

Your factorialCalculator should produce the correct result.

assert.strictEqual(factorialCalculator(6), 720);
assert.strictEqual(factorialCalculator(9), 362880);
assert.strictEqual(factorialCalculator(11), 39916800);

Your resultMsg should contain a string in a format Factorial of [num] is [factorial].

assert.strictEqual(resultMsg, `Factorial of ${num} is ${factorialCalculator(num)}`);
assert.notMatch(__helpers.removeJSComments(code), /Factorial of \d{1,2} is \d+/);

You should output the value of resultMsg to the console.

assert.match(__helpers.removeJSComments(code), /console\.log\(resultMsg\)\s*;?\s?$/m);

--seed--

--seed-contents--

--solutions--

const num = 5;

function factorialCalculator(n) {
  let result = 1;

  for (let i = 2; i <= n; i++) {
    result *= i;
  }

  return result;
}

const factorial = factorialCalculator(num);
const resultMsg = `Factorial of ${num} is ${factorial}`;
console.log(resultMsg);