Code sample for verifying signature from LINE webhook

x-line-signature.js

let text = JSON.stringify(req.body)

text = text.replace(/([\u2700-\u27BF]|[\uE000-\uF8FF]|\uD83C[\uDC00-\uDFFF]|\uD83D[\uDC00-\uDFFF]|[\u2011-\u26FF]|\uD83E[\uDD10-\uDDFF])/g, (e) => {
  return "\\u" + e.charCodeAt(0).toString(16).toUpperCase() + "\\u" + e.charCodeAt(1).toString(16).toUpperCase()
})

const signature = crypto.createHmac('SHA256', LINE_CHANNEL_SECRET).update(text).digest('base64').toString()
if (signature !== req.headers['x-line-signature']) {
  return res.status(401).send('Unauthorized')
}

Thanks for the video & this gist, it helped solve my issue

The above code is a little broken though, it tries to escape 2 characters in all cases, even though the regex can match single unicode characters. This would result in NaNs polluting the string and causing the incorrect signature to be generated.

This replacer arrow function should work better:

(emojiChars) =>
    emojiChars
      .split('')
      .map((c) => `\\u${c.charCodeAt(0).toString(16).toUpperCase()}`)
      .join('')

Also, I'm not sure exactly what characters you specifically seek to match, but if it's emojis, using the built in unicode matchers might be cover more cases, i.e. /\p{Emoji_Presentation}/gu