JavaScript Higher-Order Functions

What are Higher-Order Functions?

Functions that take functions as arguments or return functions.

``` ┌─────────────────────┐ │ Higher-Order │ │ Function │ │ ┌───────────────┐ │ │ │ Takes function │ │ │ │ OR │ │ │ │ Returns func │ │ │ └───────────────┘ │ └─────────────────────┘ ```

Examples

```javascript // Function that takes function function operate(a, b, operation) { return operation(a, b); }

operate(5, 3, (x, y) => x + y); // 8

// Function that returns function function multiplyBy(factor) { return (number) => number * factor; }

const double = multiplyBy(2); double(5); // 10 ```

Key Takeaway

Higher-order functions work with other functions. Enable powerful patterns. Essential for functional programming.