Escrow Contract Example for NEAR in JavaScript

This is an example of an escrow contract written in JavaScript for the NEAR blockchain.

Requirements

• Node.js ~= 16.16.0

Running the Example

1. Install dependencies

npm install

2. Build the contract

npm run build

3. Run the tests

npm test

What this Example Covers

1. How to write a smart contract in JavaScript

   a. How to perform cross-contract calls and pass data among them in JavaScript

2. How to write integration tests for a smart contract in JavaScript

Flows Covered in the Example

1. User A purchases a product in-escrow from User B
2. User A purchases a product in-escrow from User B and cancels the purchase
3. User A purchases a product in-escrow from User B while User B owns no products
4. User A purchases a product in-escrow from User B and approves the purchase
5. User A purchases a product in-escrow from User B and a day passes without approval
6. User A purchases a product in-escrow from User B and attempts to transfer the product to User C

Detailed Guide in Running the Example

---

Required Accounts

your-testnet-account-id        # <-- Your usual testnet account
your-escrow-testnet-account-id # <-- The testnet account holding this escrow contract/program
your-assets-testnet-account-id # <-- The testnet account holding the assets contract/program
your-asset-owner-account-id    # <-- The testnet account that owns the assets seeking $NEAR for them
your-buyer-account-id          # <-- The testnet account that owns $NEAR seeking to buy assets

---

1. Login to your NEAR account

near login

2. Create sub accounts for deploying the contracts

near create-account --accountId <your-escrow-testnet-account-id> --masterAccount <your-testnet-account-id> --initialBalance <your-escrow-testnet-account-balance>

near create-account --accountId <your-assets-testnet-account-id> --masterAccount <your-testnet-account-id> --initialBalance <your-assets-testnet-account-balance>

3. Create sub accounts to simulate users executing a transaction

near create-account --accountId <your-asset-owner-account-id> --masterAccount <your-testnet-account-id> --initialBalance <your-asset-owner-account-balance>

near create-account --accountId <your-buyer-account-id> --masterAccount <your-testnet-account-id> --initialBalance <your-buyer-account-balance>

4. Deploy the Contracts

near deploy --wasmFile build/escrow.wasm --accountId <your-escrow-testnet-account-id>

near deploy --wasmFile build/assets.wasm --accountId <your-assets-testnet-account-id>

5. Initialize the Assets Contract

near call <your-assets-testnet-account-id> init '{"owner_id": "<your-asset-owner-account-id>", "total_supply": "1000", "escrow_contract_id": "<your-escrow-testnet-account-id>", "asset_price": "100000000000000000000000"}' --accountId <your-assets-testnet-account-id>

6. Perform a Purchase on Escrow

near call <your-escrow-testnet-account-id> purchase_in_escrow '{"seller_account_id": "<your-asset-owner-account-id>", "asset_contract_id ": "<your-assets-testnet-account-id>"}' --accountId <your-buyer-account-id> --amount 0.11 --gas=300000000000000

7. Check the Balance of the Buyer Account

near view <your-assets-testnet-account-id> get_account_assets '{"account_id": "<your-buyer-account-id>"}'

near state <your-asset-owner-account-id>

8. Approve the Purchase

near call <your-escrow-testnet-account-id> approve_purchase '{}' --accountId <your-buyer-account-id>