SMS Utility using Twilio

smsUtility.js

const twilio = require('twilio');

const TAG = 'smsUtility';

/**
 * Send an SMS text message.
 *
 * Example response from Twilio:
 * {
 *   "account_sid": "ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
 *   "api_version": "2010-04-01",
 *   "body": "McAvoy or Stewart? These timelines can get so confusing.",
 *   "date_created": "Thu, 30 Jul 2015 20:12:31 +0000",
 *   "date_sent": "Thu, 30 Jul 2015 20:12:33 +0000",
 *   "date_updated": "Thu, 30 Jul 2015 20:12:33 +0000",
 *   "direction": "outbound-api",
 *   "error_code": null,
 *   "error_message": null,
 *   "from": "+15017122661",
 *   "messaging_service_sid": "MGXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
 *   "num_media": "0",
 *   "num_segments": "1",
 *   "price": null,
 *   "price_unit": null,
 *   "sid": "MMXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
 *   "status": "sent",
 *   "subresource_uris": {
 *     "media": "/2010-04-01/Accounts/ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/Messages/SMXXXXXXXXXXXXXXXXXXXXXXXX/Media.json"
 *   },
 *   "to": "+15558675310",
 *   "uri": "/2010-04-01/Accounts/ACXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/Messages/SMXXXXXXXXXXXXXXXXXXXX.json"
 * }
 *
 * @param {string} locale The recipient user ISO standard locale.
 * @param {string} msg The message to send. The character limit for a single SMS message is 160 characters; however,
 *                     most modern phones and networks support concatenation and segmenting and rebuild messages up
 *                     to 1600 characters. Messages not using GSM-7 encoding are limited to 67 characters. Large
 *                     messages are segmented into 153 character segments and sent individually then rebuilt by the
 *                     recipients device. For example, a 161 character message will be sent as two messages, one with
 *                     153 characters and the second with 8 characters. Messages containing any UCS-2 characters are
 *                     limited to 67 characters and will be concatenated into 67 character message segments, even if
 *                     the messages contain less than 160 characters. Use the following tool for testing message
 *                     splitting: http://chadselph.github.io/smssplit/
 * @param {string} recipient The recipient phone number. The format should be like this: +15558675310, which is
 *                           standard E.164 format (https://support.twilio.com/hc/en-us/articles/223183008-Formatting-International-Phone-Numbers).
 * @param {string} sender The sender phone number or null to use the default from the configuration. This is the Twilio
 *                        number purchased (https://www.twilio.com/console/phone-numbers/incoming). Use the E.164
 *                        format.
 * @param {object} config The Twilio configuration that consists of the default sender, account SID and auth token.
 * @return {Promise} A promise with the result or error.
 */
exports.send = async (locale, msg, recipient, sender, config) => {
    if (!sender) {
        sender = config.fromNumber ? config.fromNumber : null;
    }
    if (msg && recipient) {
        console.log(`${TAG}::Sending SMS text message to ${recipient} from ${sender}.`);
        const countryCode = this.getCountryCode(locale);
        const client = twilio(config.accountSid, config.authToken);
        const recipientPhoneNumber = await this.normalizePhoneNumber(client, recipient, countryCode);
        const message = await client.messages.create({
            body: msg,
            to: recipientPhoneNumber,
            from: sender,
        });
        return message;
    }
    throw new Error(`Message or recipient is missing.`, msg, recipient);
};

/**
 * Get the country code from the locale.
 *
 * @param {string} locale The ISO standard locale.
 * @return {*} The country code or null if there was a problem.
 */
exports.getCountryCode = (locale) => {
    if (!locale || locale.length < 2) {
        return null;
    }
    return locale.slice(-2);
};

/**
 * Normalize a phone number.
 *
 * @param {object} client The Twilio client.
 * @param {string} phoneNumber The phone number to normalize.
 * @param {string} countryCode The ISO standard country code.
 * @return {Promise} A promise with the normalized phone number or error.
 */
exports.normalizePhoneNumber = (client, phoneNumber, countryCode) =>
    new Promise((resolve, reject) => {
        const hasPlus = phoneNumber.indexOf('+') !== -1;
        // Remove non-digits, which includes spaces.
        let result = phoneNumber.replace(/\D/g, '');
        // Add plus back if originally existed.
        if (hasPlus) result = `+${result}`;
        client.lookups.v2
            .phoneNumbers(result)
            .fetch({ countryCode: countryCode.toUpperCase() })
            .then((phoneInfo) => {
                console.log(`${TAG}::Twilio response for phone number validation: ${JSON.stringify(phoneInfo)}`);
                console.log(`${TAG}::The phone number, ${phoneInfo.phoneNumber} is valid.`);
                resolve(result);
            })
            .catch((error) => {
                console.error(
                    `${TAG}::Failed to validate phone number ${phoneNumber} for country ${countryCode}.`,
                    error
                );
                reject(error);
            });
    });