chore(githooks): Add pre-commit hook to validate commit messages

This should help contributors follow our conventions better :-)

Closes #446

Author: Kent C. Dodds

package.json

@@ -73,7 +73,7 @@
   },
   "config": {
     "ghooks": {
-      "pre-commit": "npm run code-checks && npm run test && npm run check-coverage"
+      "commit-msg": "node scripts/pre-commit-git-check.js && npm run code-checks && npm run test && npm run check-coverage"
     }
   },
   "description": "AngularJS directive which takes JSON representing a form and renders to HTML",

scripts/pre-commit-git-check.js

@@ -0,0 +1,29 @@
+var fs = require('fs');
+var path = require('path');
+// var test = getTests();
+var format = /(.+)\(.+\)\: (.+)(\n\n([.|\s|\S]*)(\n\n([.|\s|\S]*))?)?/;
+
+fs.readFile(path.resolve(__dirname, '../.git/COMMIT_EDITMSG'), {encoding: 'UTF-8'}, function(err, contents) {
+  if (err || !commitFollowsFormat(contents)) {
+    throw err || new Error('Commit message does not follow conventions! Run `npm run commit` to commit instead of `git commit`');
+  }
+});
+
+
+function commitFollowsFormat(contents) {
+  var parts = format.exec(contents);
+  return !!parts;
+}
+
+// TODO add specific tests for parts
+/*
+function getTests() {
+  return {
+    type: testType,
+    scope: testScope,
+    subject: testSubject,
+    body: testBody,
+    footer: testFooter
+  };
+}
+*/