如何将函数嵌入到javascript这样的函数中？

Question

I've just met with a very interesting task to solve, but I can't do it myself.

Make a function which do the following input!

console.log(foo(4)(5)(6)); // output: 120

The solution is not this:

function foo(number1,number2,number3){
  return number1 * number2 * number3;
}

In theory it has to use nested functions.

Answer 1

It is called currying . You need to return function which it's case returns a function which returns the total. Here we also use a term called closure .

 function foo(a){ return function(b) { return function(c){ return a * b * c; } } } console.log(foo(4)(5)(6)); 

With ES6 syntax

 var foo = a => b => c => a*b*c; console.log(foo(4)(5)(6)); 

For infinite levels you can do

 function foo(value){ infinite.total = value; function infinite(val) { infinite.total *= val; return infinite; } infinite.toString = function() { return infinite.total; } return infinite; } console.log(foo(4)(5)(6)(7)); var total = foo(4)(5)(6)(7); console.log(total); 

But this will output the total in that cases, when toString() is called explicitly or implicitly

Answer 2

You could use an approach for any length of repeated calls of the function with returning a function and an implementation of toString method.

 var foo = function(value) { function fn(a) { fn.value *= a; return fn; } fn.value = value; fn.toString = function () { return fn.value; }; return fn; } console.log(foo(4)(5)(6)); console.log(foo(42)); console.log(foo(42)(44)); 

Answer 3

try with currying :

function foo(number) {
  return function(number2) {
    return function(number3) {
      return number * number2  number3;
    }
  }
}

console.log(foo(5)(6)(7));

https://jsfiddle.net/mv9bm3tL/1/

More information : https://www.sitepoint.com/currying-in-functional-javascript/

Answer 4

You need nested functions - currying;

console.log(foo(4)(5)(6)); // output: 120


let first = foo(4);
let second = first(5);
let last = second(6);

console.log(last);

function foo(number1,number2,number3){
  return function(number2){
    return function(number3){
      return number1 * number2 * number3;
    }
  }
}

Answer 5

Closures in javascript will help you to achieve this.

function foo(a){
  return function(b){
    return function(c){
      return a*b*c;
    }
  }
}

console.log(foo(4)(5)(6)); //will return 120

Answer 6

Using arrow functions;

 var foo = a => b => c => a*b*c; console.log(foo(4)(5)(6));