const data = `
---
hello: world
foo: bar
---
hello: world
---

# Some article title

> "hello world"
> "foo bar"
`

const match = data.trim().match(/^(---+)[\r\n]+((?:[^\r\n]+[\r\n]+)*?)\1(?=$|[\r\n]+)/)
console.log(match[2])
console.log('***')
console.log(data.slice(match[0].length + 1))