add a prerelease check

package.json

@@ -7,6 +7,7 @@
     "asar": "^0.11.0",
     "browserify": "^13.1.0",
     "check-for-leaks": "^1.0.2",
+    "colors": "^1.1.2",
     "dotenv-safe": "^4.0.4",
     "electabul": "~0.0.4",
     "electron-docs-linter": "^2.3.3",
@@ -51,6 +52,7 @@
     "publish-to-npm": "node ./script/publish-to-npm.js",
     "prepack": "check-for-leaks",
     "prepush": "check-for-leaks",
+    "prerelease": "node ./script/prerelease",
     "release": "./script/upload.py -p",
     "repl": "python ./script/start.py --interactive",
     "start": "python ./script/start.py",

script/prerelease.js

@@ -0,0 +1,84 @@
+#!/usr/bin/env node
+
+require('colors')
+const assert = require('assert')
+const GitHub = require('github')
+const pkg = require('../package.json')
+const pass = '\u2713'.green
+const fail = '\u2717'.red
+let failureCount = 0
+
+assert(process.env.ELECTRON_GITHUB_TOKEN, 'ELECTRON_GITHUB_TOKEN not found in environment')
+
+const github = new GitHub()
+github.authenticate({type: 'token', token: process.env.ELECTRON_GITHUB_TOKEN})
+github.repos.getReleases({owner: 'electron', repo: 'electron'})
+  .then(res => {
+    releases = res.data
+    // console.log(releases)
+    const drafts = releases.filter(release => release.draft)
+    
+    check(drafts.length == 1, 'one draft exists', true)
+    const draft = drafts[0]
+    
+    check(draft.tag_name == `v${pkg.version}`, `draft release version matches local package.json (v${pkg.version})`)
+    check(draft.prerelease, 'draft is a prerelease')
+    check(draft.body.length > 50 && !draft.body.includes('(placeholder)'), 'draft has release notes')
+    
+
+    const requiredAssets = filenames(draft.tag_name).sort()
+    const extantAssets = draft.assets.map(asset => asset.name).sort()
+
+    check(requiredAssets.length === extantAssets.length, 'draft has expected number of assets')
+    requiredAssets.forEach(asset => {
+      check(extantAssets.includes(asset), asset)
+    })
+
+    process.exit(failureCount > 0 ? 1 : 0)
+  })
+
+function check (condition, statement, exitIfFail = false) {
+  if (condition) {
+    console.log(`${pass} ${statement}`)
+  } else {
+    failureCount++
+    console.log(`${fail} ${statement}`)
+    if (exitIfFail) process.exit(1)
+  }
+}
+
+function filenames (version) {
+  const patterns = [
+    'electron-{{VERSION}}-darwin-x64-dsym.zip',
+    'electron-{{VERSION}}-darwin-x64-symbols.zip',
+    'electron-{{VERSION}}-darwin-x64.zip',
+    'electron-{{VERSION}}-linux-arm-symbols.zip',
+    'electron-{{VERSION}}-linux-arm.zip',
+    'electron-{{VERSION}}-linux-armv7l-symbols.zip',
+    'electron-{{VERSION}}-linux-armv7l.zip',
+    'electron-{{VERSION}}-linux-ia32-symbols.zip',
+    'electron-{{VERSION}}-linux-ia32.zip',
+    'electron-{{VERSION}}-linux-x64-symbols.zip',
+    'electron-{{VERSION}}-linux-x64.zip',
+    'electron-{{VERSION}}-mas-x64-dsym.zip',
+    'electron-{{VERSION}}-mas-x64-symbols.zip',
+    'electron-{{VERSION}}-mas-x64.zip',
+    'electron-{{VERSION}}-win32-ia32-pdb.zip',
+    'electron-{{VERSION}}-win32-ia32-symbols.zip',
+    'electron-{{VERSION}}-win32-ia32.zip',
+    'electron-{{VERSION}}-win32-x64-pdb.zip',
+    'electron-{{VERSION}}-win32-x64-symbols.zip',
+    'electron-{{VERSION}}-win32-x64.zip',
+    'electron-api.json',
+    'electron.d.ts',
+    'ffmpeg-{{VERSION}}-darwin-x64.zip',
+    'ffmpeg-{{VERSION}}-linux-arm.zip',
+    'ffmpeg-{{VERSION}}-linux-armv7l.zip',
+    'ffmpeg-{{VERSION}}-linux-ia32.zip',
+    'ffmpeg-{{VERSION}}-linux-x64.zip',
+    'ffmpeg-{{VERSION}}-mas-x64.zip',
+    'ffmpeg-{{VERSION}}-win32-ia32.zip',
+    'ffmpeg-{{VERSION}}-win32-x64.zip'
+  ]
+  return patterns.map(pattern => pattern.replace('{{VERSION}}', version))
+}