Safe symbol

.npmrc

@@ -1 +1,2 @@
 @timeswap-labs:registry=https://npm.pkg.github.com/
+//npm.pkg.github.com/:_authToken=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

ErrorCodes.md

@@ -126,6 +126,18 @@ Cannot approve to the caller
 
 Not safe transfer
 
+### E609
+
+Approve caller is not owner nor approved for all
+
+### E610
+
+Transfer to non ERC721Receiver implementer
+
+### E611
+
+Not approved to transfer
+
 ## Callback
 
 ### E701

contracts/TimeswapConvenience.sol

@@ -60,6 +60,9 @@ contract TimeswapConvenience is IConvenience {
     /// @param _factory The address of factory contract used by this contract.
     /// @param _weth The address of the Wrapped ETH contract.
     constructor(IFactory _factory, IWETH _weth) {
+        require(address(_factory) != address(0), 'E601');
+        require(address(_weth) != address(0), 'E601');
+
         factory = _factory;
         weth = _weth;
     }

contracts/base/ERC721.sol

@@ -18,10 +18,7 @@ abstract contract ERC721 is IERC721Extended {
     }
 
     modifier isApproved(address owner, uint256 id) {
-        require(
-            owner == msg.sender || getApproved[id] == msg.sender || isApprovedForAll[owner][msg.sender],
-            'Forrbidden'
-        );
+        require(owner == msg.sender || getApproved[id] == msg.sender || isApprovedForAll[owner][msg.sender], '611');
         _;
     }
 
@@ -52,10 +49,7 @@ abstract contract ERC721 is IERC721Extended {
 
     function approve(address to, uint256 id) external override {
         address owner = ownerOf[id];
-        require(
-            owner == msg.sender || isApprovedForAll[owner][msg.sender],
-            'ERC721 :: approve : Approve caller is not owner nor approved for all'
-        );
+        require(owner == msg.sender || isApprovedForAll[owner][msg.sender], '609');
         require(to != owner, 'E605');
 
         _approve(to, id);
@@ -93,10 +87,7 @@ abstract contract ERC721 is IERC721Extended {
     function _safeMint(address to, uint256 id) internal {
         _mint(to, id);
 
-        require(
-            _checkOnERC721Received(address(0), to, id, ''),
-            'ERC721 :: _safeMint : Transfer to non ERC721Receiver implementer'
-        );
+        require(_checkOnERC721Received(address(0), to, id, ''), 'E610');
     }
 
     function _mint(address to, uint256 id) private {
@@ -144,13 +135,13 @@ abstract contract ERC721 is IERC721Extended {
             );
             if (success) {
                 returnData = _return;
-            } else if (_return.length > 0) {
+            } else if (_return.length != 0) {
                 assembly {
                     let returnDataSize := mload(_return)
                     revert(add(32, _return), returnDataSize)
                 }
             } else {
-                revert('ERC721 :: _checkOnERC721Received : Transfer to non ERC721Receiver implementer');
+                revert('E610');
             }
             bytes4 retval = abi.decode(returnData, (bytes4));
             return (retval == 0x150b7a02);

contracts/libraries/Burn.sol

@@ -37,7 +37,7 @@ library Burn {
             )
         );
 
-        if (tokensOut.asset > 0) {
+        if (tokensOut.asset != 0) {
             weth.withdraw(tokensOut.asset);
             ETH.transfer(params.assetTo, tokensOut.asset);
         }
@@ -62,7 +62,7 @@ library Burn {
             )
         );
 
-        if (tokensOut.collateral > 0) {
+        if (tokensOut.collateral != 0) {
             weth.withdraw(tokensOut.collateral);
             ETH.transfer(params.collateralTo, tokensOut.collateral);
         }