js实现a(3)(4)(4)=48

Question

js实现a(3)(4)(4) // print 48

Answer 1

最简单最完美实现

// es6

   const mul = (x) => {

    let sum = x

    let curried = (y) => {

        sum = sum * y

        return curried

    }

    curried.toString = () => sum

    return curried

   }

    console.log(mul(1)) //1

    console.log(mul(1)(2))//2

    console.log(mul(1)(2)(3))//6

    console.log(mul(1)(2)(3)(4))//24

    ...

    

   // es5

 function mul(x){

  var sum = x

  var curried = function(y){

    sum = sum * y

    return curried

  }

  curried.toString=function(){

    return sum 

  }

  return curried

}

    console.log(mul(1)) //1

    console.log(mul(1)(2))//2

    console.log(mul(1)(2)(3))//6

    console.log(mul(1)(2)(3)(4))//24

    ...

Answer 2

var f = (function() {

    let r = 1;

    return function f(...args){

        r *= args.reduce((p, n) => p * n);

        f.valueOf = () => r;

        return f;

    }

}());

f(3)(4)(4)

Answer 3

const a = () => () => () => 48

Answer 4

var a = function(x) {

    return function(y) {

      return function(z) {

          console.log(x * y * z);

          return x * y * z;

      };

    };

};

Answer 5

Function Currying

Simple, Beautiful, Interesting

function curry(fn, ...args){

    return args.length === fn.length ? 

        fn(...args) : 

        (...next_args) => curry(fn, ...args, ...next_args); 

}

Next

function mul(a, b, c){

    return a * b * c; 

}

// mul(3, 4, 4); => 48 

let a = curry(mul); 

a(3)(4)(4); 

// => 48 

a(3, 4, 4); 

// => 48 

a(3)(4, 4); 

// => 48 

a()()()()()(3, 4)(4); 

// => 48 

S

Answer 6

let total;

function a(m){

    total = m;

    return function(n){

        return a(m*n)

    }

}

a(3)(4)(4)

console.log(total)  //48