柯里化
function currying (fn, ...arg1) {
if (arg1.length >= fn.length) {
return fn(...arg1)
}
return function (...arg2) {
return currying(fn, ...arg1, ...arg2)
}
}
求和
function add (...rest1) {
const fn = function (...rest2) {
rest1.push(...rest2)
return fn
}
fn.toString = function () {
return rest1.reduce((a, b) => a + b)
}
return fn
}
