Build an Optional Arguments Sum Function - Build an Optional Arguments Sum Function

JavaScript
1

Tell us what’s happening:

I do not understand the reason why I cannot pass step 5 since I have addressed the situation where undefined is explicitly passed into the func

Your code so far

function addTogether(para1, para2 = null) {
  console.log(para2)
  if (typeof para1 === "number" && typeof para2 === "number") {
    return para1 + para2;
  }
  if (typeof para1 === "number" && para2 === null) {
    const innerFunction = function (para) {
      if (typeof para === "number") {
        return para1 + para;
      }
    };
    return innerFunction;
  }

  return undefined;
}


console.log(addTogether(5, undefined));

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36

Challenge Information:

Build an Optional Arguments Sum Function - Build an Optional Arguments Sum Function
https://www.freecodecamp.org/learn/full-stack-developer/lab-optional-arguments-sum-function/build-an-optional-arguments-sum-function

Optional Arguments Sum Function
2

This line is showing

[Function: innerFunction]

which is not undefined.

3

because with your approach you are unable to distinguish between addTogether(5) and addTogether(5, undefined), in both cases the second argument becomes null

it looks like that to solve this lab there is a feature needed that is not taught in the curriculum before it

4

Is destructuring not taught yet?

5

yes, but I do not see how to solve this with destructuring alone

I have opened this

7 
function addTogether(para1, ...paras) {
  let arrLength = paras.length;
  let [para2] = paras;
  if (typeof para1 !== "number") {
    return undefined;
  } //确保para1一定为数字
  if (typeof para2 === "number") {
    return para1 + para2;
  } //去除para2为数字的情况

  if (typeof para2 !== "number") {
    if (arrLength === 0) {
      const innerFunction = function (para) {
        if (typeof para === "number") {
          return para1 + para;
        }
      };
      return innerFunction;
    }
    return undefined;
  }//处理para2为非数字的情况
} //...剩余语法将参数包装成一个不定量参数数组

console.log(addTogether(2, 3));//5
console.log(addTogether(23.4, 30));//53.4
console.log(addTogether("2", 3));//undefined
console.log(addTogether("https://www.youtube.com/watch?v=dQw4w9WgXcQ"));//undefined
console.log(addTogether(5));//[Function: innerFunction]
console.log(addTogether(5)(7));//12
console.log(addTogether(2)([3]));//undefined
console.log(addTogether(2, "3"));//undefined
console.log(addTogether(5, undefined));//undefined

I`ve worked out!!! Thanks But to be honest,I really did not know rest parameter syntax can be used in func paras…:thinking:

8

That is my bad.:rofl: I was almost insane at that time when I was thinking about how to figure it out using what I`ve learned before.I think I am alittle bit Incoherent before I post my code…

1 Like
9

that’s why I have opened the issue, it’s not taught in the curriculum

3 Likes
10

I was wondering how! I was searching how to figure out how to check the number of arguments online, and yeah. Arguments.length is not taught in the curriculum yet.

11

Arrays in JavaScript have a special length property that returns the number of elements in the array. You can access this property using the length keyword. For example:

let fruits = ["apple", "banana", "orange"];
console.log(fruits.length); // 3

Another key characteristic of arrays in JavaScript is that they are dynamic, meaning that their size can change after they are created. You can add or remove elements from an array using various array methods, such as push(), pop(), shift(), unshift(), splice(), and more. These methods will be taught in upcoming lectures.

Array.length has been taught in the first lesson of introducing Array.

3 Likes
12

Yes, but the arguments object hasn’t been