feat(curriculum): add factorial lab (freeCodeCamp#55889)

Co-authored-by: Dario-DC <[email protected]>

Author: zairahira

client/i18n/locales/english/intro.json

@@ -1955,7 +1955,10 @@
       "dvnt": { "title": "164", "intro": [] },
       "ekdb": { "title": "165", "intro": [] },
       "ezek": { "title": "166", "intro": [] },
-      "vabq": { "title": "167", "intro": [] },
+      "lab-factorial-calculator": {
+        "title": "Build a Factorial Calculator ",
+        "intro": ["In this lab, you will build a factorial calculator."]
+      },
       "lgfm": { "title": "168", "intro": [] },
       "kgtw": { "title": "169", "intro": [] },
       "ljmq": { "title": "170", "intro": [] },

client/src/pages/learn/front-end-development/lab-factorial-calculator/index.md

@@ -0,0 +1,9 @@
+---
+title: Introduction to the Build a Factorial Calculator
+block: lab-factorial-calculator
+superBlock: front-end-development
+---
+
+## Introduction to the Build a Factorial Calculator
+
+In this lab, you will build a factorial calculator.

curriculum/challenges/_meta/lab-factorial-calculator/meta.json

@@ -0,0 +1,11 @@
+{
+  "name": "Build a Factorial Calculator ",
+  "isUpcomingChange": true,
+  "usesMultifileEditor": true,
+  "blockType": "lab",
+  "dashedName": "lab-factorial-calculator",
+  "order": 167,
+  "superBlock": "front-end-development",
+  "challengeOrder": [{ "id": "66c07238b01053abaf812065", "title": "Build a Factorial Calculator" }],
+  "helpCategory": "JavaScript"
+}

curriculum/challenges/english/25-front-end-development/lab-factorial-calculator/66c07238b01053abaf812065.md

@@ -0,0 +1,133 @@
+---
+id: 66c07238b01053abaf812065
+title: Build a Factorial Calculator
+challengeType: 14
+dashedName: build-a-factorial-calculator
+---
+
+# --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.
+1. Create a function named `factorialCalculator` that takes a number as an argument and returns the factorial of that number.
+1. 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.
+1. You should call the `factorialCalculator` function with with `num` as the argument and assign the result to the variable `factorial`.
+1. You should store the final output in the format `Factorial of [num] is [factorial]` and assign it to the variable `resultMsg`.
+1. You should output the value of `resultMsg` to the console.
+
+# --hints--
+
+You should have a `num` variable.
+
+```js
+assert.isDefined(num);
+```
+
+You should assign a value to the `num` variable
+
+```js
+assert.isNotNull(num);
+```
+
+The value of `num` should be between `1` and `20`.
+
+```js
+assert.isAtLeast(num, 1);
+assert.isAtMost(num, 20);
+```
+
+The `num` value should be a number.
+
+```js
+assert.isNumber(num);
+```
+
+You should have a function named `factorialCalculator`.
+
+```js
+assert.isFunction(factorialCalculator);
+```
+
+The `factorialCalculator` function should take a number as an argument.
+
+```js
+assert.match(factorialCalculator.toString(), /\s*factorialCalculator\(\s*\w+\s*\)/);
+```
+
+The factorial of `5` should return `120`.
+
+```js
+assert.strictEqual(factorialCalculator(5), 120);
+```
+
+The factorial of `7` should return `5040`.
+
+```js
+assert.strictEqual(factorialCalculator(7), 5040);
+```
+
+For `5`, the `resultMsg` should contain `Factorial of 5 is 120`.
+
+```js
+assert.strictEqual(resultMsg, 'Factorial of 5 is 120');
+```
+
+You should call your `factorialCalculator` function with the `num` variable as the argument.
+
+```js
+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.
+
+```js
+assert.isDefined(factorial);
+assert.strictEqual(factorial, factorialCalculator(num));
+```
+
+Your `factorialCalculator` should produce the correct result.
+
+```js
+assert.strictEqual(factorialCalculator(6), 720);
+assert.strictEqual(factorialCalculator(9), 362880);
+assert.strictEqual(factorialCalculator(11), 39916800);
+```
+
+You should output the value of `resultMsg` to the console.
+
+```js
+assert.match(__helpers.removeJSComments(code), /console\.log\(resultMsg\)\s*;?\s?$/m);
+```
+
+# --seed--
+
+## --seed-contents--
+
+```js
+
+```
+
+# --solutions--
+
+```js
+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);
+```