How do closures enable partial application and currying

Q: How do closures enable partial application and currying

Difficulty: 5/10

closures, partial application, currying

Closures can be used to implement partial application and currying, techniques that involve creating new functions by fixing a subset of arguments from an original function. This allows for more flexible and reusable function compositions.

Scenario Questions

0-2 years experience

1Write a function `multiply(a, b)` and then create a partially applied version that always multiplies by 2 using a closure. How would you call it?
2If you have a function `add(x) { return function(y) { return x + y; }; }`, what does `add(5)(3)` return and why?
3Given `const greet = prefix => name => console.log(prefix + name);`, how would you create a `sayHello` function that always uses the prefix 'Hello, ' and use it to greet 'Alice'?

Follow-up Questions

Can you walk me through the execution context for the inner function?
How would you test that your partially applied function preserves `this` correctly?
What alternatives would you consider if performance becomes a concern?