Is there an error thrown when a JavaScript function is executed in the following pattern: "xyz()()"?

Question

Is there an error thrown when a JavaScript function is executed in the following pattern: "xyz()()"?

 let calculateSum = function() {
    console.log(arguments.length);
 }
 calculateSum(1)(2)(3);

Can anyone help with resolving the "not a function" error being thrown by this script? I am running it in NodeJs environment.

javascript function

Answer 1

Answer №1

For the code to function properly, recursiveSum must return a function.

The error occurs because you are attempting to execute the result of recursiveSum(1) as a function, but it is actually undefined. Essentially, you are trying to call undefined(2)(3).

You can make modifications like this:

function currySum(x) {
  return function(y) {
    return function(z) {
      return x + y + z;
    }
  }
}

console.log(currySum(1)(2)(3));

If you require a varying number of arguments and want to utilize currying syntax, check out some of the questions referenced by Bergi in a comment: this one, that one, another one, or here.

Alternatively, create an actual variadic function:

function sum() {
  var total = 0;
  for (let num of arguments) {
    total += num;
  }
  return total;
}

// Summing multiple arguments
console.log(sum(1, 2, 3, 4));
// Summing all numbers in an array
console.log(sum.apply(null, [1, 2, 3, 4]));

Answer 2

For the code to function properly, recursiveSum must return a function.

The error occurs because you are attempting to execute the result of recursiveSum(1) as a function, but it is actually undefined. Essentially, you are trying to call undefined(2)(3).

You can make modifications like this:

function currySum(x) {
  return function(y) {
    return function(z) {
      return x + y + z;
    }
  }
}

console.log(currySum(1)(2)(3));

If you require a varying number of arguments and want to utilize currying syntax, check out some of the questions referenced by Bergi in a comment: this one, that one, another one, or here.

Alternatively, create an actual variadic function:

function sum() {
  var total = 0;
  for (let num of arguments) {
    total += num;
  }
  return total;
}

// Summing multiple arguments
console.log(sum(1, 2, 3, 4));
// Summing all numbers in an array
console.log(sum.apply(null, [1, 2, 3, 4]));

Is there an error thrown when a JavaScript function is executed in the following pattern: "xyz()()"?

Answer №1

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