build: add version script for npm version releases

package.json

@@ -34,7 +34,8 @@
     "lint": "eslint . && node ./scripts/lint-readme-list.js",
     "test": "mocha --reporter spec --bail",
     "test-ci": "nyc --reporter=lcov --reporter=text npm test",
-    "test-cov": "nyc --reporter=html --reporter=text npm test"
+    "test-cov": "nyc --reporter=html --reporter=text npm test",
+    "version": "node scripts/version-history.js && git add HISTORY.md"
   },
   "keywords": [
     "http",

scripts/version-history.js

@@ -0,0 +1,63 @@
+'use strict'
+
+var fs = require('fs')
+var path = require('path')
+
+var HISTORY_FILE_PATH = path.join(__dirname, '..', 'HISTORY.md')
+var MD_HEADER_REGEXP = /^====*$/
+var VERSION = process.env.npm_package_version
+var VERSION_PLACEHOLDER_REGEXP = /^(?:unreleased|(\d+\.)+x)$/
+
+var historyFileLines = fs.readFileSync(HISTORY_FILE_PATH, 'utf-8').split('\n')
+
+if (!MD_HEADER_REGEXP.test(historyFileLines[1])) {
+  console.error('Missing header in HISTORY.md')
+  process.exit(1)
+}
+
+if (!VERSION_PLACEHOLDER_REGEXP.test(historyFileLines[0])) {
+  console.error('Missing placeholder version in HISTORY.md')
+  process.exit(1)
+}
+
+if (historyFileLines[0].indexOf('x') !== -1) {
+  var versionCheckRegExp = new RegExp('^' + historyFileLines[0].replace('x', '.+') + '$')
+
+  if (!versionCheckRegExp.test(VERSION)) {
+    console.error('Version %s does not match placeholder %s', VERSION, historyFileLines[0])
+    process.exit(1)
+  }
+}
+
+historyFileLines[0] = VERSION + ' / ' + getLocaleDate()
+historyFileLines[1] = repeat('=', historyFileLines[0].length)
+
+fs.writeFileSync(HISTORY_FILE_PATH, historyFileLines.join('\n'))
+
+function getLocaleDate () {
+  var now = new Date()
+
+  return zeroPad(now.getFullYear(), 4) + '-' +
+    zeroPad(now.getMonth() + 1, 2) + '-' +
+    zeroPad(now.getDate(), 2)
+}
+
+function repeat (str, length) {
+  var out = ''
+
+  for (var i = 0; i < length; i++) {
+    out += str
+  }
+
+  return out
+}
+
+function zeroPad (number, length) {
+  var num = number.toString()
+
+  while (num.length < length) {
+    num = '0' + num
+  }
+
+  return num
+}