Javascript SDK

Discover the JavaScript Software Development Kit (SDK) for Ola, allowing you to build applications using JavaScript.


Before using the Ola JavaScript SDK, ensure that your project includes the following packages:

  • ethers: A comprehensive Ethereum wallet implementation and utilities in JavaScript (and TypeScript).

  • @sin7y/ola-abi-wasm: A WebAssembly package for handling ABI encoding and decoding within the Ola ecosystem.

  • @sin7y/ola-crypto: A WebAssembly package providing cryptographic functionalities for the Ola ecosystem.

These packages are necessary for the SDK to function correctly, offering vital utilities and cryptographic operations needed for blockchain interactions.

Install the packages via npm:

npm i ethers@6.10.0 @sin7y/ola-abi-wasm @sin7y/ola-crypto


To get started with the Ola JavaScript SDK, install it via npm:

npm i @sin7y/ola-js-sdk

This command adds the Ola JS SDK to your project, making it ready for use in your applications.


After installing the required packages, you need to initialize the WebAssembly packages at the entry point of your project. This step is crucial for preparing the ABI and cryptographic functionalities for use.

Initializing @sin7y/ola-abi-wasm

import { init as initOlaAbiWasm } from '@sin7y/ola-abi-wasm';

// Initialize the ABI WASM module
initOlaAbiWasm().then(() => {
 console.log('@sin7y/ola-abi-wasm initialized successfully.');
}).catch(error => {
 console.error('Failed to initialize @sin7y/ola-abi-wasm:', error);

Initializing @sin7y/ola-crypto

import { init as initOlaCrypto } from '@sin7y/ola-crypto';

// Initialize the Crypto WASM module
initOlaCrypto().then(() => {
 console.log('@sin7y/ola-crypto initialized successfully.');
}).catch(error => {
 console.error('Failed to initialize @sin7y/ola-crypto:', error);

Make sure these initialization steps are performed before you use any functionality provided by the Ola JavaScript SDK. This ensures that all necessary modules are loaded and ready to execute their respective operations.


The Ola JavaScript SDK supports the following key functionalities:

  • setPubkey: This method is used for the initial registration of an account on the Ola blockchain. It is a crucial step for new users to start interacting with the blockchain.

  • invoke: Use this method to send transactions on the Ola blockchain. It enables the execution of various operations, such as transferring assets or interacting with smart contracts.

  • call: This method is designed for querying contract data. It allows read-only access to the state of smart contracts, making it possible to retrieve information without submitting a transaction.

  • Poseidon Hash: The Ola JavaScript SDK includes support for the Poseidon hash function, a highly efficient and secure hash function designed for use in zero-knowledge proofs and other blockchain-related cryptographic operations. This addition makes it easy for developers to compute hashes directly within their JavaScript or Node.js applications.

Here's a quick overview of how to use the Ola JS SDK in your project:

Generating an OlaWallet

You can generate an OlaWallet using an Ethereum private key as follows:

async function generateAccount() {
 const ethPrivateKey = "your_ethereum_private_key";
 const ethWallet = new ethers.Wallet(ethPrivateKey);
 const chainId = 1027;
 const olaWallet = await OlaWallet.fromETHSignature(ethWallet);
 olaWallet.connect("", chainId);
 return olaWallet;

Replace your_ethereum_private_key with your actual Ethereum private key.

Using OlaWallet for Blockchain Operations

The OlaWallet instance can be used to perform various operations on the Ola blockchain, including account registration, transaction sending, and contract data querying.

Registering an Account

Use the setPubKey method to register a new account on the Ola blockchain:

// Example
const olaWallet = await generateAccount();
const txHash = await olaWallet.setPubKey();
console.log("Transaction Hash:", txHash);

Sending Transactions

To send transactions, use the invoke method:

// Example
const contracAddress = "your_contract_address";
const abi = [{ name: "set", type: "function", inputs: [{ name: "d", type: "u32" }], outputs: [] }];
const params = [{ U32: 2000 }];
const txHash = await olaWallet.invoke(abi, "set(u32)", contracAddress, params);
console.log("Invoke Transaction Hash:", txHash);

The invoke method is used to send transactions that interact with smart contracts.

  async invoke(
    abi: Array<any>,
    method: string,
    to: string,
    params: Array<any>,
    options?: { nonce: number }
  ): string

Here's a breakdown of its parameters:

  • abi: This represents the Application Binary Interface (ABI) of the contract. The ABI is a JSON-formatted array defining how to serialize and deserialize data to and from the blockchain. It allows the SDK to understand the contract's structure, including its methods and types.

  • method: This is the function signature within the contract you wish to call. It specifies which function of the smart contract will be invoked.

  • to: This is the destnation contract address.

  • params: These are the parameters to pass to the function being called. The parameters should match the expected types defined in the contract's ABI.

  • options: Developers can use custom nonce on their purpose, if null, OlaWallet would use getNonce api to query the nonce of the address.

  • Return Value: The invoke method returns a transaction hash (txHash). This hash can be used to track the transaction's status on the blockchain.

Querying Contract Data

For querying contract data, the call method is used:

// Example
const abi = [{ name: "get", type: "function", inputs: [], outputs: [{ name: "", type: "u32" }] }];
let result = await<number>(abi, "get()", contracAddress, []);
console.log("Query Result:", result);

The call method is used for querying data from smart contracts without creating a transaction. This is particularly useful for reading the current state or variables within a contract.

async call<T>(
    abi: Array<any>,
    method: string,
    to: string,
    params: Array<any>
): Promise<T>

The abi, method, to, params are same as invoke's. Only the result value is different.

  • Return Value: Unlike invoke and setPubKey, the return value of call is the actual data retrieved from the smart contract function call. The data type of the return value will match the expected return type defined in the contract's ABI.##

Utilizing Poseidon Hash

The Poseidon hash function can be directly accessed through the SDK. Here's a simple guide on how to use it for hashing data:

import { poseidonHash } from '@sin7y/ola-js-sdk';

async function computeHash(data) {
 // Assuming `data` is an Uint8Array
 const hash = poseidonHash(data);
 return hash;

// Example usage
const dataToHash = Uint8Array.from([1, 2]); // Example data
 .then(hash => console.log("Computed Hash:", hash))
 .catch(error => console.error("Error computing hash:", error));

In this example, poseidonHash is a function that takes an Uint8Array as its input. This array represents the data you wish to hash. The function then computes and returns the hash as a Uint8Array of 32 length. This makes it suitable for cryptographic applications where security and efficiency are paramount.

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