Adding values to fixed array of strings only appends to the first element of the array

Question

I am trying to create a function that returns an array of strings. Sadly instead of returning an array that has N number of elements of type string, it just appends all my string values to the first and only element in the array.

pragma solidity ^0.8.7;

contract Store is Ownable {
    struct Product {
        string name;
        uint32 quantity;
        bool exists;
    }

    uint64 private productId;

    mapping(uint => Product) private products;

    constructor() {
        productId = 1;
    }

    function addProduct(string calldata name, uint32 quantity) public onlyOwner
        require(quantity > 0, "Quantity cannot be negative integer");

        productId = productId + 1;

        products[productId] = Product(name, quantity, true);
    }

    function listProducts() external view returns (string[] memory){
        string[] memory productsInfo = new string[](productId);

        if(productId < 1){
            return productsInfo;
        }

        for(uint i = 0; i < productId; i++){
            string memory info = products[i + 1].name;

            productsInfo[i] = info;
        }

        return productsInfo;
    }
}

If I add products a, b, c. The json result from colling listProducts() looks like this:

{
    "0": "string[]: a,b,c"
}

Answer 1

the contract is working. Solidity display the elements in array with commas between them. Array return start with "0" string[].

Hope it will help

// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.7;

contract Store{
    struct Product {
        string name;
        uint32 quantity;
        bool exists;
    }
     address private Owner; 
     uint64 private productId;
     mapping(uint => Product) private products;

     constructor() {
        productId = 1;
        Owner = msg.sender;
     }

     modifier onlyOwner{
        require(msg.sender == Owner, "Fail! only admin can access this 
        function!");
         _;
      }

    function addProduct(string calldata _name, uint32 _quantity) public 
    onlyOwner{
        Product memory _strucObj;
        _strucObj.name = _name;
        _strucObj.quantity = _quantity;
        products[productId -1] = _strucObj;
        productId++;
    }

    function listProducts() external view returns (string[] memory){
        string[] memory productsInfo = new string[](productId);

        if(productId < 1){
            return productsInfo;
        }

        //dash symbol used for concatenation
        string memory dash = "-";

        for(uint i = 0; i < productId; i++){
            string memory info = products[i].name;

            productsInfo[i] = info;
        }

        return productsInfo;
    }

   function CheckProductsByIndex(uint index) public view returns(string memory name)
    {
         string[] memory productsInfo = new string[](productId);
         for(uint i = 0; i < productId; i++)
         {
             string memory _toArray = products[i].name;
             productsInfo[i] = _toArray;
         }
        return productsInfo[index];
    }
}