Trampoline example

trampoline.js

function sum(n, s = 0) {
    return (n) ? () => sum(n - 1, s + n) : s
}

function trampoline(fn) {
    return function (...args) {
        let res = fn.apply(null, args)
        while (typeof res === 'function') {
            res = res()
        }
        return res
    }
}


const num = 1000000
const s = trampoline(sum)
const a = s(num)
console.log(a)