Make regex for date range (YYYY-MM-DD to YYYY-MM-DD)

date-range-regexp.js

const makeDateRangeRegexp = (from, to) => {

    const indices = Array.from('01235689')

    const unders = indices.map(i => {
        const digit = from[i]
        return digit > 0 ? from.slice(0, i) + `[0-${digit - 1}]` : null
    })

    const overs = indices.map(i => {
        const digit = to[i]
        return digit < 9 ? to.slice(0, i) + `[${+digit + 1}-9]` : null
    })

    const pattern = unders.concat(overs)
        .filter(p => p)
        .map(p => `(?!${p})`)
        .join('')
        .replace(/\[(\d)-\1]/g, '$1')

    return new RegExp('^' + pattern)

}

(f, t) => new RegExp('^' + 
  '01235689'.split('').reduce((a, i) => a.concat(
    f[i] > 0 ? f.slice(0, i) + `[0-${f[i] - 1}]` : '',
    t[i] < 9 ? t.slice(0, i) + `[${+t[i] + 1}-9]` : ''
  ), [])
  .filter(p => p)
  .map(p => `(?!${p})`)
  .join('')
)

Source: https://twitter.com/tmiya_/status/988607546368782336