2021-01-18_index_part3.js

bot.on('message', message => {
    // ping command without a prefix (exact match)
    if (message.content === 'ping') {
        const delay = Date.now() - message.createdAt
        message.reply(`**pong** *(delay: ${delay}ms)*`)
        return
    }

    // ignore all other messages without our prefix
    if (!message.content.startsWith(prefix)) return

    // let the bot introduce itself (exact match)
    if (message.content === `${prefix}who`) {
        message.channel.send(`My name is ${name} and I was created to serve!`)
        return
    }

    // user info, either call with valid user name or default to info about message author
    if (message.content.startsWith(`${prefix}whois`)) {
        // if the message contains any mentions, pick the first as the target
        if (message.mentions.users.size) {
            const taggedUser = message.mentions.users.first()
            message.channel.send(
                `User Info: ${
                    taggedUser.username
                } (account created: ${taggedUser.createdAt.toUTCString()})`,
            )
        } else {
            // default to sender if no user is mentioned
            const { author } = message
            message.reply(
                `User Self Info: ${
                    author.username
                } (account created: ${author.createdAt.toUTCString()})`,
            )
        }
    }
})