purchase-contract-service.ts

public loadPurchaseContract(contractAddress: string): Observable<PurchaseContractModel> {
    const contract: Contract = new ethers.Contract(contractAddress, this.abi, this.provider.getSigner());

    return zip(
      from(contract.key()),
      from(contract.seller()),
      from(contract.buyer()),
      from(contract.price()),
      from(contract.balanceOf()),
      from(contract.title()),
      from(contract.ipfsHash()),
      from(contract.state()),
    )
    .pipe(
        map(([key, sellerAddress, buyerAddress, weiPrice, weiBalance, title, ipfsHash, state]) => {
          // console.log(`key: ${key}, weiPrice: ${weiPrice}, state: ${state}`);
          // key: 0x706967794d6f64656c3030303500000000000000000000000000000000000000, weiPrice: 500000000000000, state: 0
          
          const product: PurchaseContractModel = {
            productKey: utils.parseBytes32String(key as ethers.utils.Arrayish),
            contractAddress,
            sellerAddress: sellerAddress as string,
            buyerAddress: (buyerAddress === ethers.constants.AddressZero) ? null : buyerAddress as string,
            price: utils.formatEther(weiPrice as ethers.utils.BigNumberish),  // $ETH
            balanceOf: utils.formatEther(weiBalance as ethers.utils.BigNumberish),  // $ETH
            title: title as string,
            ipfsHash: ipfsHash as string,
            state: state as ContractState
          };
          return product;
        }),
      )
  }