import * as MockAWS from "mock-aws-s3"; const s3 = new MockAWS.S3({ params: { Bucket: "example" } }); s3.putObject( { Bucket: "example", Key: "sea/animal.json", Body: '{"is dog":false,"name":"otter","stringified object?":true}' }, (err: MockAWS.AWSError, data: MockAWS.S3.Types.PutObjectOutput) => { s3.listObjects({ Bucket: 'example', Prefix: "sea" }, (err: any, data: any) => {}); } );