AcmeCompanyApi2.ts

class AcmeCompanyApi implements CompanyApi {
    constructor(
        private readonly forGettingCauses: ForGettingCauses,
        private readonly forOpeningClaim: ForOpeningClaim,
        private readonly authTokenRetriever: AuthTokenRetriever) {
    }

    async open(claim: Claim): Promise<OpeningResult> {
        const token = await this.authTokenRetriever.retrieveToken();
        const causes = await this.forGettingCauses.getAllFor(claim, token);
        const cause = this.findCauseInClaim(causes, claim);
        const referenceInCompany = await this.forOpeningClaim.open(claim, cause, token);
        return OpeningResult.successful(referenceInCompany, claim);
    }

    private findCauseInClaim(causes: Cause[], claim: Claim): Cause {
        let foundCause = causes.find((c) => c.causeCode === claim.causeCode());
        if (!foundCause) {
            throw new CannotFindMatchingCauseError();
        }
        return foundCause;
    }
}