Solidity Smart Contract Convention X

Just a convention to make a good-looking contract. :3 


- src
    /active: For working contracts
        /interfaces: Contains all contract interface type
        /libraries: Contains all library type
        /utils: Contains all utility type
        XXXToken.sol: ERC20 token
    /archived: For reference, sample contract, etc
    /stash: Temporary contract storage. This contract can be moved to `active` for deployment


Format standard

"prettier": "^2.4.0",
"prettier-plugin-solidity": "^1.0.0-beta.18",


"solhint": "^3.3.6",
"solhint-plugin-prettier": "^0.0.5"

Verify before commit

// package.json
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "lint": "./node_modules/.bin/solhint -f table 'src/active/**/*.sol' -w 0",
    "format": "./node_modules/.bin/prettier --write 'src/active/**/*.sol'",
    "prepare": "husky install"
  "devDependencies": {
    "husky": "^7.0.2",
    "prettier": "^2.4.0",
    "prettier-plugin-solidity": "^1.0.0-beta.18",
    "pretty-quick": "^3.1.1",
    "solhint": "^3.3.6",
    "solhint-plugin-prettier": "^0.0.5"

// .husky/pre-commit
. "$(dirname "$0")/_/"

npx pretty-quick --staged && npm run lint


  • DO use Semantic Commit Messages:
  • DO use Git Branching Model:
  • DO run format before commit
npm run format
  • DO run lint before commit
npm run lint


Style guide:

Function description

Each function must have a description as format below

   * @notice It allows the owner can set presenter to token
   * @dev This function is only callable by admin.
   * Requirements:
   * - .....
   * @param _pPresenter: the address of the token to withdraw
   * input == address(0) if you want to remove Presenter
   * @return n/a
   function fSetPresenter(address _pPresenter) external onlyOwner {
    presenter = _pPresenter;


  • Remember correct grammar and spelling
  • First character need to be Uppercase
+ DO NOT: /* @dev buy a item */
+ DO: /* @dev Buy a item */
  • Each variable or logic line should have at least an explanation
  // users[address] => UserInfo
  mapping(address => bool) public users;

  // Exclude addresses
  fAddWhitelist(owner(), true);


    1. Variables: Struct -> constant -> private -> public
    2. Events
    3. Constructor/Initializer
    2. Modifiers
    4. Function: Sort by order of function required (not visibitity)
      function0() {x = function1();}

      // Function 1 called in function, it will be below function0()
      function1() {}

    5. Group function by public/private. The private group should place at end of the file.


Folder name

Use snake_case: lowercase with underscore.

Ex: scripts_local

File name

  • Js file: snake_case -> lowercase with underscore.
  • Sol file: UpperCamelCase

Variable name

  • Variable: camelCase
  • Constant: CONSTANT_CASE
  • Prefix/Suffix rules:
    + Global public: normal without prefix or suffix (Ex: name)
    + Global private: Prefix _ (Ex: _name)
    + Function params: Prefix _ (Ex: _pName)
    + Function returns: Prefix _ (Ex: _rName)
    + Function local vars: Suffix _ (Ex: name_)
    + Function public name: Prefix f (Ex: fName() )
    + Function private name: Refix _f (Ex: _fName() )
    + Modifier name: Prefix m (Ex: mRestricted() )

Function name template

DO USE fAdd, fGet, fSet, fDel, fLen for common cases

Example: fAddUser, fGetUser, fSetUser, fDelUser, fLenUsers


  • DO USE this order of visibility type to save gas:
private -> internal (for override) -> external (for outside contract call) -> public
  • DO USE pagination for array type
  • DO USE zero address validation on owner functions to avoid accidentally case
  • DO USE readable digits. Ex: 250e6 or 250_000_000 is easier to read than 250000000
  • DO USE fixed pragma solidity version for all contracts: Ex: 0.8.4 is better than ^0.8.4
  • DO NOT USE boolean equality checking. Ex: bool z = true. DO USE: if (z) {} instead of if(z==true) {}
  • DO NOT USE modifier if not needed, it’s consume more gas than normal checking function
  • DO NOT USE array inside public Struct
  • REMOVE unused function/variables for production
  • DO Decentralization related risks:
    • DO USE Ownable to prove the Contract owner ONLY (to validate, update metadata on scan, etc)
    • DO NOT CENTRALIZE almost config functions with onlyOwner modifier.
    • DO DECENTRALIZE privilege with AccessControl or Multi-Signature.
    • DO EMIT event in all config functions.
    • DO USE multi deployer address to deploy contract.

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