Send messages but wait for delivery in Twilio Studio

delay.js

// Helper function for quickly adding await-able "pauses" to JavaScript
const sleep = (delay) => new Promise((resolve) => setTimeout(resolve, delay));

exports.handler = async (context, event, callback) => {
  // A custom delay value could be passed to the Function, either via
  // request parameters or by the Run Function Widget
  // Default to a 5 second delay
  const delay = event.delay || 5000;
  // Pause Function for the specified number of ms
  await sleep(delay);
  // Once the delay has passed, return a success message, TwiML, or
  // any other content to whatever invoked this Function.
  return callback(null, `Timer up: ${delay}ms`);
};

get-message.js

exports.handler = function(context, event, callback) {
  const messageSid = event.message_sid,
    client = context.getTwilioClient();

  if(!event.message_sid) throw "message_sid parameter is required.";

  client.messages(messageSid)
    .fetch()
    .then(message => callback(null, message))
    .catch((error) => {
      console.error(error);
      return callback(error);
    });
};

SendAndWaitUntilDelivered.json

{
  "description": "Send Message and Wait until Delivered",
  "states": [
    {
      "name": "Trigger",
      "type": "trigger",
      "transitions": [
        {
          "event": "incomingMessage"
        },
        {
          "event": "incomingCall"
        },
        {
          "event": "incomingConversationMessage"
        },
        {
          "event": "incomingRequest"
        },
        {
          "next": "send_message",
          "event": "incomingParent"
        }
      ],
      "properties": {
        "offset": {
          "x": 70,
          "y": -110
        }
      }
    },
    {
      "name": "send_message",
      "type": "send-message",
      "transitions": [
        {
          "next": "get_message",
          "event": "sent"
        },
        {
          "event": "failed"
        }
      ],
      "properties": {
        "offset": {
          "x": 90,
          "y": 70
        },
        "service": "{{trigger.message.InstanceSid}}",
        "channel": "{{trigger.message.ChannelSid}}",
        "from": "{{flow.channel.address}}",
        "to": "{{contact.channel.address}}",
        "body": "{{trigger.parent.parameters.message_body}}"
      }
    },
    {
      "name": "get_message",
      "type": "run-function",
      "transitions": [
        {
          "next": "split_1",
          "event": "success"
        },
        {
          "event": "fail"
        }
      ],
      "properties": {
        "service_sid": "ZS6e30828b12213bb75aba251c1340772f",
        "environment_sid": "ZEededfc397c488f7f5adcfccb04b06ab9",
        "offset": {
          "x": 90,
          "y": 320
        },
        "function_sid": "ZHbf33dd610a3d7a3e4f6bb80e9e2b41f1",
        "parameters": [
          {
            "value": "{{widgets.send_message.outbound.Sid}}",
            "key": "message_sid"
          }
        ],
        "url": "https://slfjkdls-8489.twil.io/get-message"
      }
    },
    {
      "name": "split_1",
      "type": "split-based-on",
      "transitions": [
        {
          "next": "set_status_to_error",
          "event": "noMatch"
        },
        {
          "next": "set_status_to_delivered",
          "event": "match",
          "conditions": [
            {
              "friendly_name": "If value equal_to delivered",
              "arguments": [
                "{{widgets.get_message.parsed.status}}"
              ],
              "type": "equal_to",
              "value": "delivered"
            }
          ]
        },
        {
          "next": "wait_a_second",
          "event": "match",
          "conditions": [
            {
              "friendly_name": "If value matches_any_of accepted,queued,sending,sent",
              "arguments": [
                "{{widgets.get_message.parsed.status}}"
              ],
              "type": "matches_any_of",
              "value": "accepted,queued,sending,sent"
            }
          ]
        }
      ],
      "properties": {
        "input": "{{widgets.get_message.parsed.status}}",
        "offset": {
          "x": -80,
          "y": 550
        }
      }
    },
    {
      "name": "wait_a_second",
      "type": "run-function",
      "transitions": [
        {
          "next": "get_message",
          "event": "success"
        },
        {
          "event": "fail"
        }
      ],
      "properties": {
        "service_sid": "ZS6e30828b12213bb75aba251c1340772f",
        "environment_sid": "ZEededfc397c488f7f5adcfccb04b06ab9",
        "offset": {
          "x": -270,
          "y": 320
        },
        "function_sid": "ZH87400457a91e2dbc451817d1f68fd6e8",
        "parameters": [
          {
            "value": "1000",
            "key": "delay"
          }
        ],
        "url": "https://slfjkdls-8489.twil.io/delay"
      }
    },
    {
      "name": "set_status_to_delivered",
      "type": "set-variables",
      "transitions": [
        {
          "event": "next"
        }
      ],
      "properties": {
        "variables": [
          {
            "value": "delivered",
            "key": "status"
          }
        ],
        "offset": {
          "x": 320,
          "y": 790
        }
      }
    },
    {
      "name": "set_status_to_error",
      "type": "set-variables",
      "transitions": [
        {
          "event": "next"
        }
      ],
      "properties": {
        "variables": [
          {
            "value": "error",
            "key": "status"
          }
        ],
        "offset": {
          "x": -40,
          "y": 800
        }
      }
    }
  ],
  "initial_state": "Trigger",
  "flags": {
    "allow_concurrent_calls": true
  }
}