Async tx confirmer

TransactionConfirmer.ts

export class ConfirmTransactionFailureError extends Error {
    constructor(signature: string) {
        super("Failed to confirm transaction:" + signature);
        this.name = "ConfirmTransactionFailure";
    }
}

export class TransactionConfirmer {
    private subscriptionId: number;
    private signatures = new Map<string, Logs>();

    constructor(connection: Connection, keypair: Keypair) {
        this.subscriptionId = connection.onLogs(
            keypair.publicKey,
            (logs, __ctx) => {
                if (this.signatures.has(logs.signature)) {
                    this.signatures.set(logs.signature, logs);
                }
            },
            "finalized"
        );
    }

    public confirm = async (
        signature: string,
    ): Promise<Logs> => new Promise(
        (resolve, reject) => {
            this.signatures.set(signature, undefined);
            let iterations = 0;
            const interval = setInterval(() => {
                if (iterations >= 120) {
                    clearInterval(interval);
                    this.signatures.delete(signature);
                    return reject(new ConfirmTransactionFailureError(signature));
                }
                iterations++;
                const confirmed = this.signatures.get(signature);
                if (confirmed) {
                    const logs = structuredClone(confirmed);
                    clearInterval(interval);
                    this.signatures.delete(signature);
                    if (logs.signature !== signature) {
                        return reject(new ConfirmTransactionFailureError(`Signature mismatch logs signature: ${logs.signature} tx signature: ${signature}`));
                    }
                    if (logs.err) {
                        return reject(logs);
                    }
                    if (logs.logs && logs.logs.length > 0 && logs.logs.slice(-1)[0].match(/success/) !== null) {
                        return resolve(logs);
                    }
                    return reject(new ConfirmTransactionFailureError(logs.signature));
                }
            }, 500);
        }
    );
}