personal-voicemail.js

exports.handler = function (context, event, callback) {

        /***** configuration *****/

        const phoneNumber = 'YOUR_PHONE_NUMBER';
        const timeout = event.Timeout || 12;

        const secureRecordingLinks = false;

        const voiceOpts = {
                'voice': 'alice',
                'language': 'en-US'
        };

        const reject = [
                // To block a caller, add the E164 formatted number here
        ];

        let rejectMessage = "You are calling from a restricted number. Goodbye.";

        /***** end configuration *****/


        let thisFunction = 'https://' + context.DOMAIN_NAME + '/personal-voicemail';

        function shouldReject() {
                return reject.length && event.From && reject.includes(event.From);
        }

        function rejectInbound() {
                let twiml = new Twilio.twiml.VoiceResponse();
                if (rejectMessage) {
                        twiml.say(rejectMessage, voiceOpts);
                }
                twiml.hangup();
                return twiml;
        }

        function handleInbound() {
                const dialParams = {
                        'action': thisFunction
                };

                if (event.CallerId) {
                        dialParams.callerId = event.CallerId;
                }

                if (timeout) {
                        dialParams.timeout = timeout;
                }

                const twiml = new Twilio.twiml.VoiceResponse();
                twiml.dial(dialParams, phoneNumber);

                return twiml;
        }
        
        function redirect() {
                const twiml = new Twilio.twiml.VoiceResponse();
                twiml.redirect(thisFunction);
                return twiml;
        }

        switch (true) {
                case event.CallStatus === 'queued':
                        callback(null, redirect());
                        break;
                case event.CallStatus === 'ringing':
                        callback(null, shouldReject() ? rejectInbound() : handleInbound());
                        break;
                default:
                        callback();
        }
};