SOURCE

function add(...num) {
    const sum = num.reduce((acc, cur) => acc + cur, 0)
    console.log(sum)
    return add.bind(this, ...num)
}

function add2(...num) {
    let args = [...num]

    let next = function (...s) {
        args.push(...s);
        return next
    }

    next.toString = function () {
        return args.reduce((acc, cur) => acc + cur);
    }

    // next.valueOf = function () {
    //     return args.reduce((acc, cur) => acc + cur);
    // }

    return next
}


// add(1)(2)(2,5)

console.log(add2(2)(3)(4,5))