flea-market-contract-service.ts

public removePurchaseContract(productKey: string): Observable<string> {

    const bytes32Key = utils.formatBytes32String(productKey);
    const token = this.contractToken.removeContractByKey(bytes32Key);
  
    return from(token)
      .pipe(
        switchMap((tx: any) => {
          console.log('removeContractByKey Transaction', tx);
          // Wait for transaction to be mined 
          // Returned a Promise which would resolve to the TransactionReceipt once it is mined.
          return from(tx.wait()).pipe(
            tap((txReceipt: any) => console.log('TransactionReceipt: ', txReceipt)),
            // The receipt will have an "events" Array, which will have
            // the emitted event from the Contract. The "logRemovePurchaseContract(address sender, bytes32 key))
            // call is the last event.
            map(txReceipt => txReceipt.events.pop()),
            tap(txEvent => console.log('txEvent: ', txEvent)),
            map(txEvent => {
              // retrieve the key parameter value from the event
              const key = txEvent.args['key'];
              return utils.parseBytes32String(key as ethers.utils.Arrayish)
            }),

          )
        }))
  }