feat: download high resolution imgs (#6)

License: MIT
Signed-off-by: Henrique Dias <hacdias@gmail.com>

lib/xkcd.js

@@ -1,4 +1,5 @@
 const fetch = require('node-fetch')
+const path = require('path')
 
 async function getLatestId () {
   const raw = await fetch(`https://xkcd.com/info.0.json`)
@@ -6,10 +7,26 @@ async function getLatestId () {
   return data.num
 }
 
+async function getImage (url) {
+  const ext = path.extname(url)
+  const url2x = `${path.dirname(url)}/${path.basename(url, ext)}_2x${ext}`
+
+  let res = await fetch(url2x)
+  if (!res.ok) {
+    res = await fetch(url)
+  }
+
+  if (!res.ok) {
+    throw new Error('bad image request')
+  }
+
+  return res.buffer()
+}
+
 async function getComic (id) {
   const raw = await fetch(`https://xkcd.com/${id}/info.0.json`)
   const data = await raw.json()
-  const img = await (await fetch(data.img)).buffer()
+  const img = await getImage(data.img)
 
   return { data, img }
 }