使用compose函数和Array.reduce进行JavaScript函数编程

Question

I am new to JavaScript Functional programming. In code below, compose can't work without setInterval outside it and clear as the first argument also does't give the compose initial value.

So my question is how can compose work without the setInterval ?

 const clear = () => console.clear() const f1 = () => 2 const log = message => console.log(message) const compose = (...fns) => arg => fns.reduce( (composed, f) => f(composed), arg ) setInterval( compose(clear, f1, log), 1000 ) 

Answer 1

compose(...fns) returns a function. When used with setInterval , it is being called implicitly by the JavaScript engine.

If you want to use it directly, you can do something like:

 const clear = () => console.clear() const f1 = () => 2 const log = message => console.log(message) const compose = (...fns) => arg => fns.reduce( (composed, f) => f(composed), arg ) compose(clear, f1, log)();