Example showing flow for constructor dependency injection

CreateAccount.ts

// This is in the RN app. It shows the Client logic (CreateAccount), the RN Authenticator implementation and the service that calls the blockchain.

import { User as UserSdk, Authenticator, AuthenticatorLevel } from 'tonomy-id-sdk';

class RNAuthenticator implements Authenticator {
    createPermission(level: AuthenticatorLevel, privateKey: string, challenge: string) {
        // stores the key in keychain with the challenge
        return 'publicKey';
    }

// signs data with a private key
    signData(level: AuthenticatorLevel, dataToSign: string | Uint8[], challenge: string) {
// check the key
// sign with the private key
}

}

// React component example (not using react for readability)
// just shows the logic
class CreateAccount {
    user: UserSdk;

    constructor(authenticator: Authenticator) {
        this.user = new UserSdk(new RNAuthenticator());
    }

    // User presses create account button, and that calls this function in the client
    createAccount(masterPassword: string) {
        this.user.createAccount(masterPassword);
    }
}

user.ts

// this shows part of the SDK library with Authenticator interpace, and a User class library.
enum AuthenticatorLevel { Password, PIN, Fingerprint, Local };

interface Authenticator {
    // creates a new secure key and returns the public key
    createPermission(level: AuthenticatorLevel, privateKey: string, challenge: string): string

// to ensure the most forward compatibility, we send all arguments as properties of an object which can then more easily be depreciated and upgraded over time. a version property can also be added
    createPermission(options: any): string

    // signs data with a private key
    signData(level: AuthenticatorLevel, dataToSign: string | Uint8[], challenge: string): string

    // retrieve a public key from a stored private key
    getKey(level: AuthenticatorLevel): string
}

class User {
    authenticator: Authenticator;
    id: IDSmartContract;

    constructor(_authenticator: Authenticator) {
        this.authenticator = _authenticator;
        this.id = new IDSmartContract();
    }

    createAccount(accountName: string, masterPassword: string) {
        const { privateKey, salt } = this.generatePrivateKeyFromPassword(masterPassword);

        const passwordPublicKey = this.authenticator.createPermission(AuthenticatorLevel.Password, privateKey, masterPassword);

        this.id.create(accountName, passwordPublicKey, salt);
    }

    signTx(accountName: string, masterPassword: string) {
        const { privateKey, salt } = this.generatePrivateKeyFromPassword(masterPassword);

        const passwordPublicKey = this.authenticator.createPermission(AuthenticatorLevel.Password, privateKey, masterPassword);

        this.id.create(accountName, passwordPublicKey, salt);
    }



    generatePrivateKeyFromPassword(password: string) {
        // creates a key based on secure (hashing) key generation algorithm like Argon2 or Scrypt
        return {
            privateKey: 'xxxx',
            salt: 'yyyy'
        }
    }
}

// wrapper class that has js interface to call the smart contract
class IDSmartContract {
    // calls the ID smart contract create() function to create the account
    create(accountName: string, passwordPublicKey: string, salt: string) {
        // creates the new account with the public key and account name,
        // and stores the salt on chain for later user to re-derive the private key with the password
    }
}

export default User;
export { Authenticator, AuthenticatorLevel };