Solidity Examples

This is a compilation of Solidity examples that I worked on while learning about Solidity and developing smart contracts.

Nearly all the smart contracts are accompanied by tests, so feel free to experiment with them to gain a deeper understanding of the Solidity programming language and the business logic within the contracts themselves.

Table of Contents

Basic

1. Hello World
2. First App
3. Primary Data Types
4. Variables
5. Constants
6. Immutable
7. Reading & Writing to a State Variable
8. Ether and Wei
9. Gas and Gas Price
10. If and Else
11. For and While Loop
12. Mapping
13. Array
14. Enum
15. Structs
16. Data Locations - Storage, Memory, and Calldata
17. Transient Storage 🚧
18. Function
19. View and Pure Functions
20. Error
21. Function Modifier
22. Events
23. Constructor
24. Inheritance
25. Shadowing Inherited State Variables
26. Calling Parent Contracts
27. Visibility
28. Interface
29. Payable
30. Sending Ether (transfer, send, call)
31. Fallback
32. Call
33. Delegatecall
34. Function Selector
35. Calling Other Contract
36. Contract that creates other contracts
37. Try Catch
38. Import
39. Library
40. ABI Encode
41. ABI Decode
42. Hashing with Keccak256
43. Verifying Signature
44. Gas Saving Techniques
45. Bitwise Operators
46. Unchecked Math
47. Assembly Variable
48. Assembly Conditional Statements
49. Assembly Loop
50. Assembly Error
51. Assembly Math

Applications

1. Ether Wallet
2. Multi-Sig Wallet
3. Merkle Tree
4. Iterable Mapping
5. ERC20
6. ERC721
7. ERC1155
8. Gasless Token Transfer 🚧
9. Simple Bytecode Contract
10. Precompute Contract Address with Create2
11. Minimal Proxy Contract
12. Upgradeable Proxy 🚧
13. Deploy Any Contract

Contributors

We enthusiastically welcome pull requests from all contributors. By actively participating in submitting examples, we firmly believe that others will find them invaluable when embarking on their Solidity journey.

License

The software is available as open source under the terms of the MIT License.

Preparation

npm i -g pnpm
pnpm install

Git commit

Note

Please use Conventional Commits for your commits.

e.g.

{emoji}<type>[scope]: <subject>
[body]
[footer]

Types

Important

type should be one of belows.

add
adopt
apply
build
chore
config
delete
docs
feat
fix
init
refactor
remove
style
test
update
upgrade

Emoji

Important

Your commit should start with gitmoji code.
Please check the emoji code on https://gitmoji.dev/

Description	Emoji	Code
Add a dependency.	➕	:heavy_plus_sign:
Add a failing test.	🧪	:test_tube:
Add or update a .gitignore file.	🙈	:see_no_evil:
Add or update an easter egg.	🥚	:egg:
Add or update analytics or track code.	📈	:chart_with_upwards_trend:
Add or update animations and transitions.	💫	:dizzy:
Add or update assets.	🍱	:bento:
Add or update business logic.	👔	:necktie:
Add or update CI build system.	👷	:construction_worker:
Add or update code related to multithreading or concurrency.	🧵	:thread:
Add or update code related to validation.	🦺	:safety_vest:
Add or update comments in source code.	💡	:bulb:
Add or update compiled files or packages.	📦️	:package:
Add or update configuration files.	🔧	:wrench:
Add or update contributor(s).	👥	:busts_in_silhouette:
Add or update development scripts.	🔨	:hammer:
Add or update documentation.	📝	:memo:
Add or update healthcheck.	🩺	:stethoscope:
Add or update license.	📄	:page_facing_up:
Add or update logs.	🔊	:loud_sound:
Add or update secrets.	🔐	:closed_lock_with_key:
Add or update seed files.	🌱	:seedling:
Add or update snapshots.	📸	:camera_flash:
Add or update text and literals.	💬	:speech_balloon:
Add or update the UI and style files.	💄	:lipstick:
Add or update types.	🏷️	:label:
Add sponsorships or money related infrastructure.	💸	:money_with_wings:
Add, update, or pass tests.	✅	:white_check_mark:
Add, update, or remove feature flags.	🚩	:triangular_flag_on_post:
Begin a project.	🎉	:tada:
Catch errors.	🥅	:goal_net:
Critical hotfix.	🚑️	:ambulance:
Data exploration/inspection.	🧐	:monocle_face:
Deploy stuff.	🚀	:rocket:
Deprecate code that needs to be cleaned up.	🗑️	:wastebasket:
Downgrade dependencies.	⬇️	:arrow_down:
Fix a bug.	🐛	:bug:
Fix CI Build.	💚	:green_heart:
Fix compiler / linter warnings.	🚨	:rotating_light:
Fix security or privacy issues.	🔒️	:lock:
Fix typos.	✏️	:pencil2:
Improve accessibility.	♿️	:wheelchair:
Improve developer experience.	🧑‍💻	:technologist:
Improve performance.	⚡️	:zap:
Improve SEO.	🔍️	:mag:
Improve structure / format of the code.	🎨	:art:
Improve user experience / usability.	🚸	:children_crossing:
Infrastructure related changes.	🧱	:bricks:
Internationalization and localization.	🌐	:globe_with_meridians:
Introduce breaking changes.	💥	:boom:
Introduce new features.	✨	:sparkles:
Make architectural changes.	🏗️	:building_construction:
Merge branches.	🔀	:twisted_rightwards_arrows:
Mock things.	🤡	:clown_face:
Move or rename resources (e.g.: files, paths, routes).	🚚	:truck:
Perform database related changes.	🗃️	:card_file_box:
Perform experiments.	⚗️	:alembic:
Pin dependencies to specific versions.	📌	:pushpin:
Refactor code.	♻️	:recycle:
Release / Version tags.	🔖	:bookmark:
Remove a dependency.	➖	:heavy_minus_sign:
Remove code or files.	🔥	:fire:
Remove dead code.	⚰️	:coffin:
Remove logs.	🔇	:mute:
Revert changes.	⏪️	:rewind:
Simple fix for a non-critical issue.	🩹	:adhesive_bandage:
Update code due to external API changes.	👽️	:alien:
Upgrade dependencies.	⬆️	:arrow_up:
Work in progress.	🚧	:construction:
Work on code related to authorization, roles and permissions.	🛂	:passport_control:
Work on responsive design.	📱	:iphone:
Write bad code that needs to be improved.	💩	:poop:
Write code drunkenly.	🍻	:beers: