Added new if-then-else example (Closes #71) (#139)

* Added new if-then-else example (Closes #71)

* docs: minor updates

* refactor: rename folder

* style: format code for consistency and readability

---------

Co-authored-by: JeelRajodiya <[email protected]>

Author: RoaaFouda

content/05-Conditional-Validation/06-Expanding-If-then-else/code.ts

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+const code: any = {
+  type: "object",
+  properties: {
+    name: {
+      type: "string",
+    },
+    age: {
+      type: "integer",
+    },
+    grade: {
+      type: "number",
+      minimum: 0,
+      maximum: 10,
+    },
+    recommendationLetter: {
+      type: "string",
+    },
+    personalStatement: {
+      type: "string",
+    },
+  },
+  required: ["name", "grade"],
+};
+
+let solution = structuredClone(code);
+solution = {
+  ...solution,
+  if: {
+    properties: {
+      grade: {
+        minimum: 8,
+      },
+    },
+  },
+  then: {
+    required: ["recommendationLetter"],
+    not: { required: ["personalStatement"] },
+  },
+  else: {
+    required: ["personalStatement"],
+    not: { required: ["recommendationLetter"] },
+  },
+};
+const testCases = [
+  {
+    input: {
+      name: "John Doe",
+      age: 20,
+      grade: 8,
+      recommendationLetter: "Dr. Smith's letter",
+    },
+    expected: true,
+  },
+  {
+    input: {
+      name: "John Doe",
+      age: 20,
+      grade: 5,
+      personalStatement: "I love engineering..",
+    },
+    expected: true,
+  },
+  {
+    input: {
+      name: "John Doe",
+      grade: 5,
+      personalStatement: "",
+    },
+    expected: true,
+  },
+  {
+    input: {
+      name: "John Doe",
+      age: 20,
+      grade: 9,
+    },
+    expected: false,
+  },
+  {
+    input: {
+      name: "John Doe",
+      age: 20,
+      grade: 5,
+    },
+    expected: false,
+  },
+  {
+    input: {
+      name: "John Doe",
+      age: 20,
+      grade: 5,
+      recommendationLetter: "",
+      personalStatement: "",
+    },
+    expected: false,
+  },
+  {
+    input: {
+      name: "John Doe",
+      age: 20,
+      grade: 8,
+      recommendationLetter: "",
+      personalStatement: "",
+    },
+    expected: false,
+  },
+  {
+    input: {
+      name: "John Doe",
+      age: 20,
+      recommendationLetter: "",
+    },
+    expected: false,
+  },
+  {
+    input: {
+      age: 20,
+      grade: 8,
+    },
+    expected: false,
+  },
+];
+
+module.exports = {
+  code,
+  solution,
+  testCases,
+};

content/05-Conditional-Validation/06-Expanding-If-then-else/instructions.mdx

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+---
+title: "Expanding If-Then-Else"
+description: "Learn how to use the if-then-else keyword in JSON Schema to apply conditional validation using more than just constants."
+keywords: "if-then-else, conditional validation, JSON Schema, not, minimum, subschema"
+---
+
+# Expanding If-Then-Else
+So far, you've learned how to use if-then-else for conditionals. This lesson will show how they can be combined with different validation rules, not just constants!
+
+## Using with  not Keyword
+The `not` keyword allows you to negate a condition (or any schema rule), meaning a property must not match a specified type or constraint. For example, the following schema ensures that the name property can be anything except a string:
+```json highlightLineStart={5} highlightLineEnd={5}
+{
+  "type": "object",
+  "properties": {
+   "name": {
+      "type": {"not": {"type": "string"}}
+    } 
+  }
+}
+```
+
+Using the `not` keyword with the `if-else` keyword can look something like this:
+
+**Example Schema**
+```json highlightLineStart={15} highlightLineEnd={23}
+{
+  "type": "object",
+  "properties": {
+    "status": { 
+      "type": "string", 
+      "enum": ["employed", "unemployed"] 
+      },
+    "salary": { 
+      "type": "number" 
+      },
+    "unemploymentBenefits": { 
+      "type": "number" 
+      }
+  },
+  "if": { 
+    "properties": {
+       "status": { "const": "employed" } 
+    } 
+  },
+  "then": { 
+    "not": { "required": ["unemploymentBenefits"] 
+    } 
+  }
+}
+```
+- If `status` is `"employed"`, the `unemploymentBenefits` field **must not** be present.  
+- If `status` is `"unemployed"`, `unemploymentBenefits` field can be present.
+
+This demonstrates that conditionals in JSON Schema can be combined with various keywords, allowing for more flexible validation rules.
+
+## Task
+
+```json 
+{
+    "name": "John Doe",
+    "age": 20,
+    "grade": 8,
+    "recommendationLetter": "Dr. Smith's letter",   
+}
+```
+
+You are given the [schema](https://json-schema.org/learn/glossary#schema) for the same JSON document in the <SideEditorLink/>. Modify the schema to enforce the below condition using `if-then-else`:
+
+- **If** `grade` is **greater that or equal to 8**, **then** the `recommendationLetter` field must be present, and the `personalStatement` field must **NOT** be present.
+- Else if `grade` is **lower than 8**, **then** the `personalStatement` field must be present, and the `recommendationLetter` field must **NOT** be present..
+
+> **Hint:** Use the `minimum` keyword to specify the constraint of greater than or equal to 8.