Create DecenLibrary.sol

Created the Library Contract

hardhat/contracts/DecenLibrary.sol

@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+contract DecenLibrary {
+    //Variables
+    mapping(address => string[]) public _uploadedCIDS; //Variable to track the uploaded cids of an address
+
+    //FUNCTION 01
+    //first upload
+    function _upload(string[] memory _cidsToUpload) public {
+        _uploadedCIDS[msg.sender] = _cidsToUpload;
+    }
+
+    //FUNCTION 02
+    //subsequent uploads
+    function _subsequentUpload(string[] memory _newCidsToUpload) public {
+        // string[] calldata _uploadedCIDSArray;
+        string[] memory _existingCIDS;
+        _existingCIDS = _getListOfUploadedCIDS(msg.sender);
+        string[] memory _updatedCIDS;
+        _updatedCIDS = _addTwoArrays(msg.sender, _newCidsToUpload); //helper function 1
+        _uploadedCIDS[msg.sender] = _updatedCIDS;
+    }
+
+    //FUNCTION 03
+    //view all your uploads
+    function _getListOfUploadedCIDS(address _address)
+        public
+        view
+        returns (string[] memory)
+    {
+        return _uploadedCIDS[_address];
+    }
+
+    //HELPER FUNCTION 01
+    function _addTwoArrays(address _address, string[] memory _newCidsToUpload)
+        public
+        returns (string[] memory)
+    {
+        string[] storage _updatedCIDS = _uploadedCIDS[_address]; //create an array that references the existing one in the mapping
+        for (uint8 i = 0; i < _newCidsToUpload.length; i += 1) {
+            _updatedCIDS.push(_newCidsToUpload[i]); //add the items from the new one to the old one
+        }
+        return _updatedCIDS; //final array is updated
+    }
+
+    //HELPER FUNCTION 02
+    //return ether balance of the wallet calling the function
+    function viewBalance() internal view returns (uint256) {
+        return msg.sender.balance;
+    }
+}