Boostnote/browser/lib/findNoteTitle.js

const frontMatterRegex = /^\-{3,}/

export function findNoteTitle (value) {
  const splitted = value.split('\n')
  let title = null
  let isInsideCodeBlock = false

  if (frontMatterRegex.exec(splitted[0])) {
    let index = 0
    while (++index < splitted.length && !frontMatterRegex.exec(splitted[index])) {
    }

    splitted.splice(0, index + 1)
  }

  splitted.some((line, index) => {
    const trimmedLine = line.trim()
    const trimmedNextLine = splitted[index + 1] === undefined ? '' : splitted[index + 1].trim()
    if (trimmedLine.match('```')) {
      isInsideCodeBlock = !isInsideCodeBlock
    }
    if (isInsideCodeBlock === false && (trimmedLine.match(/^# +/) || trimmedNextLine.match(/^=+$/))) {
      title = trimmedLine
      return true
    }
  })

  if (title === null) {
    title = ''
    splitted.some((line) => {
      if (line.trim().length > 0) {
        title = line.trim()
        return true
      }
    })
  }

  return title
}

export default {
  findNoteTitle
}