npm install -g @aws-amplify/cli

$ node -v
v11.12.0

$ amplify -v
4.26.0

pod 'Amplify', '1.1.0'
pod 'AmplifyPlugins/AWSCognitoAuthPlugin', '1.1.0'

$ pod install --repo-update

$ amplify init
Note: It is recommended to run this command from the root of your app directory
? Enter a name for the project {ここはアプリケーションの名前になるので好きなように命名してください}
? Enter a name for the environment dev
? Choose your default editor: None
? Choose the type of app that you're building ios
Using default provider  awscloudformation

? Do you want to use an AWS profile? Yes
? Please choose the profile you want to use default

$ amplify add auth

Do you want to use the default authentication and security configuration? Manual configuration

Select the authentication/authorization services that you want to use: User Sign-Up, Sign-In, connected with AWS IAM co
ntrols (Enables per-user Storage features for images or other content, Analytics, and more)

Please provide a friendly name for your resource that will be used to label this category in the project: amplify****

Please enter a name for your identity pool. amplify****_identitypool_****

Allow unauthenticated logins? (Provides scoped down permissions that you can control via AWS IAM) No

Do you want to enable 3rd party authentication providers in your identity pool? Yes

Select the third party identity providers you want to configure for your identity pool: {選択なし}

Please provide a name for your user pool: amplify****_userpool_****

Warning: you will not be able to edit these selections.
How do you want users to be able to sign in? Email

Do you want to add User Pool Groups? No

Do you want to add an admin queries API? No

Multifactor authentication (MFA) user login options: OFF

Email based user registration/forgot password: Enabled (Requires per-user email entry at registration)

Please specify an email verification subject: Your verification code

Please specify an email verification message: Your verification code is {####}

Do you want to override the default password policy for this User Pool? Yes

Enter the minimum password length for this User Pool: 8

Select the password character requirements for your userpool: Requires Lowercase, Requires Uppercase, Requires Numbers

Warning: you will not be able to edit these selections.
What attributes are required for signing up? Email, Name

Specify the app's refresh token expiration period (in days): 30

Do you want to specify the user attributes this app can read and write? No

Do you want to enable any of the following capabilities? Email Verification Link with Redirect

Do you want to use an OAuth flow? No

? Do you want to configure Lambda Triggers for Cognito? No

? Enter the URL that your users will be redirected to upon account confirmation: {ユニバーサルリンクが起動するURL、同じ手順で進めていれば今回はCloudFrontのURLになります}

? Enter the subject for your custom account confirmation email: アカウント確認

? Enter the body text for your custom account confirmation email (this will appear before the link URL): 下記のURLをクリックすることで、メールアドレスの認証が完了となります。

Successfully added resource amplify**** locally

// PoolIdとRegionは変更の必要無し
// AppClientIdに新しく追加したクライアントIDに書き換え、AppClientSecretは削除する
"CognitoUserPool": {
    "Default": {
        "PoolId": "****",
        "AppClientId": "****",
        "Region": "****"
    }
}

import Amplify
import AmplifyPlugins

_ = Amplify.Auth.fetchAuthSession(listener: { (result) in
    do {
        let session = try result.get()
        print("fetchAuthSession succcess:\(session.isSignedIn)")
    } catch {
        print("fetchAuthSession error:\(error)")
    }
})

_ = Amplify.Hub.listen(to: .auth) { (payload) in
    switch payload.eventName {
    case HubPayload.EventName.Auth.signedIn:
        // ログイン済み
    case HubPayload.EventName.Auth.signedOut:
        // ログアウト
    case HubPayload.EventName.Auth.sessionExpired:
        // セッション切れ
    default: break
    }
}

let userAttributes = [AuthUserAttribute(.name, value: userName)]
let options = AuthSignUpRequest.Options(userAttributes: userAttributes)
_ = Amplify.Auth.signUp(username: mailAddress, password: password, options: options) { result in
    switch result {
    case .success(let signUpResult):
        if case let .confirmUser(deliveryDetails, _) = signUpResult.nextStep {
            print("signUp: \(String(describing: deliveryDetails))")
        } else {
            print("signUp: complete")
        }
    case .failure(let error):
        print("signUp error: \(error)")
    }
}

_ = Amplify.Auth.signIn(username: mailAddress, password: password) { result in
    switch result {
    case .success(_):
        print("signIn success")
    case .failure(let error):
        print("signIn error: \(error)")
    }
}

let options = AuthSignOutRequest.Options(globalSignOut: true)
_ = Amplify.Auth.signOut(options: options) { (result) in
    switch result {
    case .success:
        print("signOut success")
    case .failure(let error):
        print("signOut error: \(error)")
    }
}