§ How to do partial application in JavaScript

Partial application is a technique in functional programming that allows you to create a new function with some of the arguments pre-filled. This can be useful when you want to reuse a function with the same arguments multiple times.

Here is an example of partial application in JavaScript:

function add(a, b) {
  return a + b;
}

let add5 = add.bind(null, 5);
console.log(add5(3)); // Output: 8
console.log(add5(4)); // Output: 9

In this example, the add5 function is created by partially applying the add function with the argument 5. This means that the add5 function is equivalent to calling add with the first argument fixed to 5. The add5 function is now a new function that takes one argument and returns the result of adding 5 to it.

Partial application can be useful when you want to reuse a function with the same arguments multiple times. It is a technique that is often used in functional programming. In Javascript, the most common way to implement it is by using bind method. It allows to create a new function with some of the arguments pre-filled.