Cannot find name 'Buffer'


I am developing a Nodejs mobile app using Ionic, Angular 2 and Aws Cognito. After integrating amazon-cognito-identity-js, it shows error cannot find name ‘Buffer’

AWS Cognito installed using the command: npm install --save amazon-cognito-identity-js

After adding following statement:
import { CognitoUserPool, CognitoUserAttribute, CognitoUser, AuthenticationDetails } from ‘amazon-cognito-identity-js’

getting the following error:
Cannot find name ‘Buffer’.
L1031: export type _Blob = Buffer|Uint8Array|Blob|string;
L1032: export type Boolean = boolean;