Convert HTML to Slack's mrkdwn format.
const mrkdwn = require('html-to-mrkdwn')
const html = `
<p><strong>Hello</strong> <a href="https://example.com">cruel</a> <em>world</em>!</p>
<p><img src="https://media.giphy.com/media/5xtDarEbygs3Pu7p3jO/giphy.gif"></p>
`
mrkdwn(html)
// {
// text: "*Hello* <https://example.com|cruel> _world_!\n\n<https://media.giphy.com/media/5xtDarEbygs3Pu7p3jO/giphy.gif>",
// image: "https://media.giphy.com/media/5xtDarEbygs3Pu7p3jO/giphy.gif",
// }