fix: extract into a module

lib/get-binary.js

@@ -0,0 +1,19 @@
+'use strict'
+
+const path = require('path')
+const fs = require('fs')
+
+const binPath = path.join(__dirname, '..', 'bin')
+const detailsPath = path.join(binPath, 'details')
+
+module.exports = () => {
+ if (!fs.existsSync(detailsPath)) {
+ throw new Error('ERROR: unable to locate `youtube-dl` at ' + binPath)
+ }
+
+ const details = JSON.parse(fs.readFileSync(detailsPath))
+
+ return details.path
+ ? details.path
+ : path.resolve(__dirname, '..', 'bin', details.exec)
+}

lib/youtube-dl.js

@@ -4,10 +4,8 @@ const execFile = require('child_process').execFile
 const streamify = require('streamify')
 const request = require('request')
 const hms = require('hh-mm-ss')
-const path = require('path')
 const http = require('http')
 const url = require('url')
-const fs = require('fs')
 
 const {
  isYouTubeRegex,
@@ -17,29 +15,12 @@ const {
  isString
 } = require('./util')
 
-const detailsPath = path.join(__dirname, '..', 'bin/details')
+let ytdlBinary = require('./get-binary')()
 
 const TEN_MEGABYTES = 1000 * 1000 * 10
 
 const execFileOpts = { maxBuffer: TEN_MEGABYTES }
 
-let ytdlBinary = (() => {
- if (fs.existsSync(detailsPath)) {
- const details = JSON.parse(fs.readFileSync(detailsPath))
- return details.path
- ? details.path
- : path.resolve(__dirname, '..', 'bin', details.exec)
- }
-
- if (!fs.existsSync(ytdlBinary)) {
- console.error(
- 'ERROR: unable to locate youtube-dl details in ' +
- path.dirname(ytdlBinary)
- )
- process.exit(1)
- }
-})()
-
 function youtubeDl (args, options, cb) {
  execFile(ytdlBinary, args, { ...execFileOpts, ...options }, function done (
  err,