Quick start#

Let’s make a simple custom contract. First, create npm project and install the dependencies:

npm init
yarn add assemblyscript -D
yarn add jest -D

npx asinit .

yarn add idena-sdk-as@0.0.29

After project initialization, you will have the following project folder structure:

assembly: folder with contract source code
build: folder for compiled files
node_modules: dependencies
tests: folder with tests
asconfig.json: config file for the asc compiler

Next, update asconfig.json file so that the asc compiler uses the transformation of the contract code with idena-sdk-bindgen. For this you need to add the line:

"extends": "idena-sdk-as/asconfig.json"

You are ready to write the contract code using idena-sdk-as. Exported class in the assembly/index.ts is the entry point for executing the contract.

As an example, see the code of hello-world contract.

Building#

To build the contracts use asbuild:

yarn asb

As a result, a file will be created:

/build/release/<your-project-name>.wasm

Testing#

For testing, we recommend using jest. Run the command to install it:

yarn add jest -D

Update the "test" value in your project package.json file in the scripts section as follows:

"test":"jest"

In the tests folder, create the index.test.js file.

See example of tests for hello-world contract.

To execute the contract code and run the test, you need to install and run Idena node emulator idena-contract-runner. You can build it yourself or download the executable file.

idena-sdk-as contains additional classes and methods for testing, see idena-sdk-tests.

To run tests, use the command:

yarn test

Deploying#

To deploy your contract you can use rpc.idena.io.

Connect to the Idena node
Enter your coinbase address
Select the compiled .wasm contract file
Enter unique nonce
Specify args for the contract constructor if needed
You can call the contract_estimateDeploy method to calcaulte maxfee parameter

{
  "method": "contract_Deploy",
  "params": [
    {
      "from": "0x6899...",
      "code": "0x0061736d01...",
      "nonce": "0x01",
      "args": [],
      "maxFee": 2
    }
  ],
  "id": 1,
  "key": "..."
}

Response example:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0xdeb3..."
}

As a result you will get a hash of DeployContractTx transaction. To get the address of the deployed contract, call bcn_txReceipt method for this transaction hash.