Calculate the average time to read a text

time_to_read.go

// Copyright © 2021 Alex
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

package internal

import (
        "time"
        "unicode"
)

// https://en.wikipedia.org/wiki/Words_per_minute
// Reading seems to average around 200 +- 50 words/minute for english, according to various web sources.
const avgWordsPerMin float64 = 200

func timeToRead(src []byte) time.Duration {
        words := countWords(src)
        wpm := float64(words) / avgWordsPerMin
        dur := time.Duration(wpm*60) * time.Second // We want the minimal unit of time to be seconds (roughly)
        return dur
}

func countWords(b []byte) int {
        words, inWord := 0, false
        for _, r := range b {
                if unicode.IsSpace(rune(r)) {
                        inWord = false
                } else if inWord == false {
                        inWord = true
                        words++
                }
        }
        return words
}