Merge pull request #47 from venables/revert-util-promisify

Revert `util.promisify` usage to continue supporting Node 6

.travis.yml

@@ -3,4 +3,5 @@ node_js:
   - "12"
   - "10"
   - "8"
+  - "6"
 after_success: yarn run coverage

lib/koa-helmet.js

@@ -1,7 +1,7 @@
 'use strict';
 
 const helmet = require('helmet');
-const { promisify } = require('util');
+const promisify = require('./promisify');
 
 const koaHelmet = function () {
   const helmetPromise = promisify(helmet.apply(null, arguments));

lib/promisify.js

@@ -0,0 +1,24 @@
+'use strict';
+
+/**
+ * Takes an express-style middleware and returns a promise-based version (returning a Promise,
+ * rather than calling the final argument as a callback) suitable for use with koa.
+ *
+ * @param {Function} middleware - The middleware to promisify
+ * @returns {Function} - The middleware function updated to return a Promise, not call a callback
+ */
+function koaHelmetPromisify (middleware) {
+  return function (req, res) {
+    return new Promise(function (resolve, reject) {
+      middleware(req, res, function (err) {
+        if (err) {
+          return reject(err);
+        }
+
+        return resolve();
+      });
+    });
+  };
+}
+
+module.exports = koaHelmetPromisify;

package.json

@@ -3,7 +3,7 @@
   "author": "Matt Venables <mattvenables@gmail.com>",
   "description": "Security header middleware collection for koa",
   "license": "MIT",
-  "version": "4.2.0",
+  "version": "4.2.1",
   "main": "lib/koa-helmet.js",
   "scripts": {
     "format": "eslint lib test --fix",
@@ -23,19 +23,19 @@
     "url": "git://github.com/venables/koa-helmet.git"
   },
   "engines": {
-    "node": ">= 8.0.0"
+    "node": ">= 6.0.0"
   },
   "dependencies": {
-    "helmet": "^3.18.0"
+    "helmet": "^3.15.1"
   },
   "devDependencies": {
-    "ava": "^2.0.0",
+    "ava": "^1.3.1",
     "coveralls": "^3.0.3",
-    "eslint": "^5.16.0",
-    "eslint-plugin-node": "^9.1.0",
+    "eslint": "^5.15.1",
+    "eslint-plugin-node": "^8.0.1",
     "koa": "^2.7.0",
-    "nyc": "^14.1.1",
-    "supertest": "^4.0.2"
+    "nyc": "^13.3.0",
+    "supertest": "^4.0.0"
   },
   "nyc": {
     "reporter": [

test/promisify.spec.js

@@ -0,0 +1,38 @@
+'use strict';
+
+const promisify = require('../lib/promisify');
+const test = require('ava');
+
+function passingMiddleware (req, res, next) {
+  return next();
+}
+
+function failingMiddleware (req, res, next) {
+  return next(new Error('Expected Failure'));
+}
+
+test('returns a promisified version of the middleware which resolves the Promise on success', t => {
+  let middleware = promisify(passingMiddleware);
+
+  return middleware().then(
+    () => {
+      t.pass();
+    },
+    err => {
+      t.fail(err);
+    }
+  );
+});
+
+test('returns a promisified version of the middleware which rejects the Promise on failure', t => {
+  let middleware = promisify(failingMiddleware);
+
+  return middleware().then(
+    () => {
+      t.fail('Unexpected Success!');
+    },
+    () => {
+      t.pass();
+    }
+  );
+});