polkadot_apps

Interacting with Polkadot

Setup

1. Ensure that you have recent versions of Node and Yarn
2. Install dependencies with yarn - you may also have to do yarn add @polkadot/api@beta
3. To run, node foo.js

Kinds of Calls

1. Constants - A constant feature of the chain. These are things that the API does not need to do any work to get, they can just see the value.
2. Queries - These are basically function calls to get some data.
3. Tx - Issue an actual on-chain extrinsic. Note that even though this looks like it would only contain transactions, it is for any extrinsic.
4. Events - Listening for events occurring on-chain.

Basic Connection

Connect to Kusama

See basic_connect.js

Connect to local node (could be connected to Kusama, running local chain, etc.)

See basic_connect_local.js

Reading Constants

See read_constants.js

Calling Functions

See read_account.js

Script to Check Balances

See read_any_account.js

Subscribing to Events

See display_data.js

See account_watcher.js

Transactions

See tx.js

See better_tx.js

A More Complex Script

See Anson Lau's Validator Stats script

Moving Beyond

1. Dig into the API https://polkadot.js.org/api/
2. Start programming the UI https://polkadot.js.org/ui/start/
3. polkadot.js source and links to other tutorials: https://github.com/polkadot-js/apps
4. Various CLI tools to help your development https://github.com/polkadot-js/tools
5. Dealing with types, enums, structs, etc. https://polkadot.js.org/api/start/types.basics.html