One-line HTML input renders invalid HTML output

[larsgw]

Input:

<div><div>a</div><div>b</div></div>

Output:

<div><div>a</div>
<div>b</div>
<p></div></p>

Full code:

const Showdown = require('showdown')
const converter = new Showdown.Converter()
const input = '<div><div>a</div><div>b</div></div>'
console.log(converter.makeHtml(input))

Showdown version: 1.6.4

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I'm not sure if my input is invalid (and I should expect undefined behaviour), but the output certainly is!

[tivie]

Related to #357

[tivie]

This should (hopefully) be fixed now, without much performance issues.