@gridsome/transformer-remark/lib/timeToRead.js

Markdown transformer for Gridsome

// Word count in respect of CJK characters
// Borrowed from: https://github.com/yuehu/word-count

const pattern = /[a-zA-Z0-9_\u0392-\u03c9\u00c0-\u00ff\u0600-\u06ff\u0400-\u04ff]+|[\u4e00-\u9fff\u3400-\u4dbf\uf900-\ufaff\u3040-\u309f\uac00-\ud7af]+/g

function estimateTimeToRead (text, speed) {
  const m = text.match(pattern)
  let count = 0

  // Empty string
  if (!m) {
    return 0
  }

  for (const c of m) {
    if (c.charCodeAt(0) >= 0x4e00) {
      count += c.length
    } else {
      count += 1
    }
  }

  return Math.round(count / speed) || 1
}

module.exports = {
  estimateTimeToRead
}