Function to be used with tagged ES2015 template literals

toSentence.js

function toSentence (strings, ...values) {
  const nouns = values[0] || ''
  const noun = values[1] || ''
  const verb = values[2] instanceof Array === true ? (nouns.length ? values[2][1] : values[2][0]) : ''

  const mappedString = strings.map((char, index) => {
    if (index === 0 && !nouns) {
      return `${char}${noun}`
    } else if (index === 1 && !nouns) {
      return ''
    } else if (index === 2 && verb) {
      return `${char}${verb}`
    }
    return `${char}${values[index] || ''}`
  })

  return mappedString.join('') 
}

// EXAMPLE 2
const users = ['john', 'kirby', 'leo', 'tina']
const lastUser = users.pop()

console.log(toSentence `${users.join(', ')} and ${lastUser} ${['is', 'are']} online today`)


// EXAMPLE 2
const users = ['john']
const lastUser = users.pop()

console.log(toSentence `${users.join(', ')} and ${lastUser} ${['is', 'are']} online today`)