Issue using AwsIotMqttConnectionConfigBuilder.new_mtls_builder(cert: string, private_key: string) to create MQTT connection

I am currently developing an ios app that uses ionc 5 and angular 9. I am trying to intialize an mqtt connection to the IoT core like this

let config = iot.AwsIotMqttConnectionConfigBuilder.new_mtls_builder(String(args.cert_string), String(args.private_string))
    .with_clean_session(false)
    .with_client_id(this.globals.getVariable("applicationID"))
    .with_endpoint(this.globals.getVariable("aws_endpoint"))
    .with_keep_alive_seconds(6)
    .build();
let client_bootstrap = new io.ClientBootstrap();
let client = new mqtt.MqttClient(client_bootstrap);
let connection = client.new_connection(config);
connection.connect().then((session_present) => {
    console.log("Aws iot connection successful, resuming session:", session_present);
}).catch((error) => {
    console.log("MQTT initialization error:", error);
});

But I am getting this error

MQTT initialization error: TypeError: Cannot read property 'aws_access_id' of undefined
    at create_websocket_url (ws.js:78)
    at Object.create_websocket_stream (ws.js:91)
    at MqttClient.create_websocket_stream [as streamBuilder] (mqtt.js:224)
    at MqttClient._setupStream (client.js:298)
    at new MqttClient (client.js:277)
    at new MqttClientConnection (mqtt.js:233)
    at MqttClient.new_connection (mqtt.js:110)
    at SkalaControlWebsocket.ts:1590
    at t.invoke (polyfills.js:3)
    at Object.onInvoke (core.js:4629)

I am referencing this documentation https://aws.github.io/aws-iot-device-sdk-js-v2/classes/aws_crt.awsiotmqttconnectionconfigbuilder.html. I cannot seem use AwsIotMqttConnectionConfigBuilder.new_mtls_builder to initialize an mqtt client where the certificate and private key are strings. I have made sure that they are in PEM format. Any help would be greatly appreciated. Thanks

[ConnorGitHubAccount]

Hi @jmklix I appreciate the quick response time. Yes I have seen #77 and am able to create a MQTT connection the with the AwsIotMqttConnectionConfigBuilder.new_with_websockets() method shown toward the bottom of the post. The only thing about his method is the authentication uses IAM credentials(AWS Access Key Id, AWS Secret access key, and AWS session token). I would like to establish a connection using strings in PEM format of certificate and private key pairs provided by the IoT core. This would be much much more preferable for our application.

[bretambrose]

If you’re using nodejs then you can make certificate-based mqtt connections to IoT core, but if you’re not, your only option is websockets.