koehr.ing/bin/blog.ts

#!/bin/env deno run

import { globber } from "https://deno.land/x/globber@0.1.0/mod.ts"

interface FileIndex {
  title: string
  slug: string
  abstr: string
  date: string
  readingTimeSlow: number
  readingTimeFast: number
}

const cwd = './blog/'
const outputPath = './blog/index.md'

const fileIndex: FileIndex[] = []

const fileIter = globber({ cwd, include: ["????-??-??*.md"] })
const decoder = new TextDecoder('utf-8')
const encoder = new TextEncoder()

const header = `*Sometimes, I write long-form articles about a topic that I find interesting. I use this as a way to dive deeper into a topic, while often create an example project on the side.*

Last updated: ${(new Date()).toISOString().slice(0,10)}

`

const template = `<article class="blog">
  <time datetime="%DATE%">%DATE%</time>
  <div>
    <a href="/blog/%SLUG%.html">%TITLE%</a>
    <span class="reading-time">(%READING_TIME_FAST% to %READING_TIME_SLOW% minutes)</span>
  </div>
  <p>
    %ABSTRACT%
  </p>
</article>
`

function getAbstract(lines: string[]): string {
  const sep = '<!-- more -->'
  const sep2 = '<!--more-->'
  let foundSep = false

  return lines.slice(3).filter(line => {
    if (foundSep) return false
    if (line.indexOf(sep) >= 0 || line.indexOf(sep2) >= 0) {
      foundSep = true
      return false
    }
    return true
  }).join('\n').trim()
}

function render(fi: FileIndex) {
  return template
    .replaceAll('%DATE%', fi.date)
    .replaceAll('%TITLE%', fi.title)
    .replaceAll('%SLUG%', fi.slug)
    .replaceAll('%ABSTRACT%', fi.abstr)
    .replaceAll('%READING_TIME_FAST%', fi.readingTimeFast)
    .replaceAll('%READING_TIME_SLOW%', fi.readingTimeSlow)
}

for await (const file of fileIter) {
  if (file.isDirectory) {
    console.log('ignoring directory', file.relative)
    break
  }

  const path = file.absolute
  const date = file.relative.slice(0, 10)
  const slug = file.relative.slice(0, -3)

  const raw = await Deno.readFile(path)
  const text = decoder.decode(raw)
  const words = text.trim().split(/\s+/).length
  const lines = text.split('\n')

  const title = lines[0].slice(2)
  const abstr = getAbstract(lines)

  // calculates estimated reading times: [fast, slow]
  // wpm numbers from https://thereadtime.com/
  const readingTimeFast = Math.round(words / 207)
  const readingTimeSlow = Math.round(words / 167)

  fileIndex.push({ title, slug, abstr, date, readingTimeFast, readingTimeSlow })
}

const output = fileIndex
.sort((a, b) => a.date.localeCompare(b.date) * -1)
.map(render)
.join('\n')

Deno.writeFile(outputPath, encoder.encode(header+output))