**Higher-order functions** are functions that take other functions as arguments or return functions, enabling more flexible and reusable code by allowing behavior and data to be passed in dynamically.

## Why Use Higher-Order Functions?
- **Abstraction**: Hide away implementation details and focus on what needs to be done.
-  **Reusability**: Create flexible functions that work with different operations.
-  **Cleaner Code**: Avoid repetitive logic and use declarative constructs.

```js
// Higher-order function: accepts a function as an argument
function letPerson(person, fn) {
  return fn(person); // Executes the behavior (fn) with the person data
}

// Behavior function 1: authentication based on role
function authenticate(person) {
  const delay = person.level === 'admin' ? 500000 : 100000;
  for (let i = 0; i < delay; i++) {
    // Simulated heavy computation (authentication)
  }
  return `Access granted to ${person.name}`;
}

// Behavior function 2: introduce person
function introducePerson(person) {
  return `Hi! My name is ${person.name}`;
}

// Example persons
const user = { name: 'Valentin', level: 'user' };
const admin = { name: 'Marko', level: 'admin' };

// Usage examples
console.log(letPerson(user, authenticate)); // Access granted to Valentin
console.log(letPerson(admin, authenticate)); // Access granted to Marko
console.log(letPerson(user, sing)); // La la la... my name is Valentin


```

**This example illustrates:**

 **1.Abstraction:**
- The function **letPerson** abstracts away the details of how the behavior (authentication, introducing, etc.) is performed.
- The caller just needs to provide the behavior function (**fn**) and the person object. **letPerson** does not care what the behavior is internally.
- This hides the implementation details of specific actions and focuses on the “what” — applying some behavior to a person.


 **2.Reusability:**
 
 - The higher-order function **letPerson** that works with any behavior function you pass in.
 - This allows you to reuse the same **letPerson** function for different operations (authenticate, introducePerson, or any other behavior you want to add later).
 - The behavior functions themselves (authenticate, introducePerson) are modular and reusable for different person objects.

 **3.Cleaner Code:**
 - Instead of writing separate functions that manually handle the person object and execute their logic, you use a declarative, functional approach.
 -  Avoid repeating the code structure for passing the person and executing the behavior.
 -  The logic for each behavior is separated, clear, and easy to maintain.
 

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Higher Order Functions in Javascript