Cannot access the function inside the other function

Question

This is how my inventoryList() function is called and I cannot change it.

 if (operationInfo[0] === 'add') {
            inventoryList().add(operationInfo[1]);

But I have a method inside my inventoryList function like below but it states obj.add is not a function? why?

function inventoryList(){

    const add = (name) => {
        // adds string to inv and if item exists doesn't add. Adds to log also as objects maintain no position
        if(!(name in inv)){
            inv[name] = name;
            entries.push(name)
        }
      };
}

Answer 1

In order to use the add function, you should return if from your inventoryList function.

function inventoryList() {
   const add = (name) => {
      if (!(name in inv)) {
         inv[name] = name;
         entries.push(name)
      }
   };

   return { add };
}

Althought, if you are going to use it like that, I recommend changing the inventoryList to class with add as its method.

class InventoryList {
   add(name) {
      if (!(name in inv)) {
         inv[name] = name;
         entries.push(name)
      } 
   }
}

You can than use it like this

const invList = new InventoryList();

if (operationInfo[0] === 'add') {
   invList.add(operationInfo[1]);
}

Answer 2

inventoryList is not returning anything. Return an object which contains reference to the function you want to execute. Also _add is an inner function which is private to inventoryList so have to expose it to use it

 function execute() { inventoryList().add('hello') } function inventoryList() { const _add = (name) => { console.log(name) // rest of code }; return { add: _add, // add other function if it is there } }

 <button onclick='execute()'>Execute</button>