Templates Example

Template arrays are JSSON’s superpower for handling tabular data. Let’s see them in action!

Basic Template

The simplest template array:

JSSON

users [
template { name, age, job, height }
João, 19, Student, 1.75
Maria, 25, Teacher, 1.65
Pedro, 30, Doctor, 1.80
Ana, 22, Nurse, 1.68
]

JSON Output

{
"users": [
  {
    "name": "João",
    "age": 19,
    "job": "Student",
    "height": 1.75
  },
  {
    "name": "Maria",
    "age": 25,
    "job": "Teacher",
    "height": 1.65
  },
  {
    "name": "Pedro",
    "age": 30,
    "job": "Doctor",
    "height": 1.8
  },
  {
    "name": "Ana",
    "age": 22,
    "job": "Nurse",
    "height": 1.68
  }
]
}

Template with Map Transformation

Add computed fields and transform data:

JSSON

routes [
template { path, method }

map (item) = {
  path = "/api/v1/" + item.path
  method = item.method
  auth = true
  version = "v1"
}

users, GET
posts, POST
comments, DELETE
products, GET
]

JSON Output

{
"routes": [
  {
    "path": "/api/v1/users",
    "method": "GET",
    "auth": true,
    "version": "v1"
  },
  {
    "path": "/api/v1/posts",
    "method": "POST",
    "auth": true,
    "version": "v1"
  },
  {
    "path": "/api/v1/comments",
    "method": "DELETE",
    "auth": true,
    "version": "v1"
  },
  {
    "path": "/api/v1/products",
    "method": "GET",
    "auth": true,
    "version": "v1"
  }
]
}

Product Catalog

Real-world e-commerce example:

JSSON

products [
template { id, name, price, category }

map (p) = {
  id = p.id
  name = p.name
  price = p.price
  category = p.category
  currency = "USD"
  inStock = true
  url = "/products/" + p.id
}

1, "Laptop Pro 15", 1299.99, electronics
2, "Wireless Mouse", 29.99, accessories
3, "USB-C Cable", 12.99, accessories
4, "Monitor 27", 399.99, electronics
5, "Keyboard Mechanical", 89.99, accessories
]

JSON Output

{
"products": [
  {
    "id": 1,
    "name": "Laptop Pro 15",
    "price": 1299.99,
    "category": "electronics",
    "currency": "USD",
    "inStock": true,
    "url": "/products/1"
  },
  {
    "id": 2,
    "name": "Wireless Mouse",
    "price": 29.99,
    "category": "accessories",
    "currency": "USD",
    "inStock": true,
    "url": "/products/2"
  },
  {
    "id": 3,
    "name": "USB-C Cable",
    "price": 12.99,
    "category": "accessories",
    "currency": "USD",
    "inStock": true,
    "url": "/products/3"
  },
  {
    "id": 4,
    "name": "Monitor 27",
    "price": 399.99,
    "category": "electronics",
    "currency": "USD",
    "inStock": true,
    "url": "/products/4"
  },
  {
    "id": 5,
    "name": "Keyboard Mechanical",
    "price": 89.99,
    "category": "accessories",
    "currency": "USD",
    "inStock": true,
    "url": "/products/5"
  }
]
}

Test Data

Perfect for seeding databases:

testUsers [
template { email, password, role, verified }

map (u) = {
  email = u.email
  password = u.password
  role = u.role
  verified = u.verified
  createdAt = "2025-11-23T00:00:00Z"
  active = true
}

"admin@test.com", "admin123", admin, true
"user1@test.com", "user123", user, true
"user2@test.com", "user123", user, false
"guest@test.com", "guest123", guest, false
]

API Endpoints Configuration

endpoints [
template { name, path, method, public }

map (e) = {
  name = e.name
  path = "/api" + e.path
  method = e.method
  public = e.public
  rateLimit = 100
  timeout = 5000
}

getUsers, "/users", GET, false
getUser, "/users/:id", GET, false
createUser, "/users", POST, false
getPosts, "/posts", GET, true
getPost, "/posts/:id", GET, true
createPost, "/posts", POST, false
]

Try It Yourself!

1. Save any example above to a .jsson file
2. Run: jsson -i template.jsson -o template.json
3. See the structured JSON output!

Experiment Ideas

Add More Fields

users [
template { name, age, email, city, country }
João, 25, "joao@test.com", "São Paulo", Brazil
Maria, 30, "maria@test.com", Tokyo, Japan
]

Complex Transformations

employees [
template { firstName, lastName, department }

map (emp) = {
  fullName = emp.firstName + " " + emp.lastName
  email = emp.firstName + "@company.com"
  department = emp.department
  employeeId = emp.firstName + "-" + emp.department
  active = true
}

João, Silva, Engineering
Maria, Santos, Marketing
]

Multiple Templates

users [
template { name, email }
João, "joao@test.com"
Maria, "maria@test.com"
]

products [
template { name, price }
Laptop, 999.99
Mouse, 29.99
]

What’s Next?

• Templates Guide — Complete guide to template arrays
• Demo Example — See basic JSSON features
• Syntax Reference — Full syntax documentation

Templates make JSSON incredibly powerful for structured data! 🚀