npm-should-install.patch

From c39e95ae6d41939e73568bea5782228d8590b953 Mon Sep 17 00:00:00 2001
From: Joey Baker <joey@byjoeybaker.com>
Date: Thu, 31 Mar 2016 11:17:44 -0700
Subject: [PATCH] Add: bin/should-install

Small script that warns if the dependencies are different from the last
time the script was run.
---
 bin/lib/should-install.js | 61 +++++++++++++++++++++++++++++++++++++++++++++++
 bin/should-install        | 22 +++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 bin/lib/should-install.js
 create mode 100755 bin/should-install

diff --git a/bin/lib/should-install.js b/bin/lib/should-install.js
new file mode 100644
index 0000000..0a47247
--- /dev/null
+++ b/bin/lib/should-install.js
@@ -0,0 +1,61 @@
+import {createWriteStream, readFile} from 'fs'
+import md5 from 'md5'
+import mkdirp from 'mkdirp'
+import path from 'path'
+import {parallel} from 'async'
+
+const ENOENT = 'ENOENT'
+const CWD = process.cwd()
+const CACHE_DIR = path.join(CWD, '.cache')
+const CACHE_PATH = path.join(CACHE_DIR, 'should-install.json.cache')
+const PKG_PATH = path.join(CWD, 'package.json')
+
+const getDepsHash = (done) => {
+  readFile(PKG_PATH, (err, pkg) => {
+    if (err) return void done(err)
+
+    const json = JSON.parse(pkg.toString())
+    const hash = md5(json.dependencies + json.devDependencies)
+    done(null, hash)
+  })
+}
+
+const readCache = (done) => {
+  readFile(CACHE_PATH, (err, cache) => {
+    if (err) {
+      if (err.code === ENOENT) done(null, {})
+      else done(err)
+    }
+    else done(null, JSON.parse(cache.toString()))
+  })
+}
+
+const writeCache = (cache, done) => {
+  createWriteStream(CACHE_PATH)
+    .on('error', done)
+    .on('finish', done)
+    .end(JSON.stringify(cache))
+}
+
+export default ({checkpoint}, complete) => {
+  parallel({
+    cacheDirExists: (done) => {
+      mkdirp(CACHE_DIR, done)
+    }
+    , depsHash: getDepsHash
+    , cache: readCache
+  }, (err, {depsHash, cache}) => {
+    if (err) return void complete(err)
+
+    const currentDiffersFromCache = depsHash !== cache.depsHash
+
+    if (checkpoint) {
+      writeCache({depsHash}, () => {
+        complete(null, currentDiffersFromCache)
+      })
+    }
+    else {
+      complete(null, currentDiffersFromCache)
+    }
+  })
+}
diff --git a/bin/should-install b/bin/should-install
new file mode 100755
index 0000000..76a3e8c
--- /dev/null
+++ b/bin/should-install
@@ -0,0 +1,22 @@
+#!/usr/bin/env node
+
+const argv = require('yargs')
+  .usage('checks a cache of package.json and the git HEAD to see if npm should install')
+  .option('checkpoint', {
+    alias: 'c'
+  , describe: 'if this is a checkpoint, the cache will be updated and used for the next comparison'
+  , default: false
+  })
+  .help('h')
+  .alias('h', 'help')
+  .epilog('License: Artistic-2.0')
+  .version(require('../package.json').version)
+  .showHelpOnFail(false, 'Specify --help for available options')
+  .argv
+
+require('babel/register')
+require('./lib/should-install.js')(argv, (err, shouldInstall) => {
+  if (err) throw err
+  else if (shouldInstall) process.exit(1)
+  else process.exit(0)
+})

package.json

+    "update-should-install-cache": "echo $(./bin/should-install --checkpoint)",
 +    "postinstall": "if [ \"${NODE_ENV-}\" = \"development\" ]; then npm run -s update-should-install-cache; fi",