chore: Implement danger for PRs (#1905)

.babelrc

@@ -0,0 +1,3 @@
+// This is solely to avoid https://github.com/danger/danger-js/issues/261
+// and should be fine to remove before much longer
+{}

dangerfile.js

@@ -0,0 +1,56 @@
+/* global danger warn fail */
+"use strict";
+
+var fs = require("fs"),
+	path = require("path"),
+
+	locater = require("locater"),
+	pinpoint = require("pinpoint"),
+	dedent = require("dedent");
+
+// Various views of changed/added files
+var jsfiles = danger.git.created_files
+		.concat(danger.git.modified_files)
+		.filter((file) => path.extname(file) === ".js"),
+
+	changelog = danger.git.modified_files.find((file) =>
+		file === "docs/change-log.md"
+	),
+
+	appfiles = jsfiles.filter((file) =>
+		file.indexOf("tests/") === -1
+	);
+
+function link(file, anchor, text) {
+	var repo = danger.github.pr.head.repo.html_url,
+		ref = danger.github.pr.head.ref;
+
+	return danger.utils.href(`${repo}/blob/${ref}/${file}${anchor || ""}`, file || text);
+}
+
+// All PRs should be targeted against `next`
+if(danger.github.pr.base.ref !== "next") {
+	warn("PRs should be based on `next`, rebase before submitting please");
+}
+
+// Any non-test JS changes should probably have a change-log entry
+if(appfiles.length && !changelog) {
+	warn(`Please include a ${link("docs/change-log.md", "changelog")} entry.`)
+}
+
+// Call out if `o.only(...)` was left in
+jsfiles
+	.filter((file) => file.indexOf("tests/") > -1)
+	.forEach((file) => {
+		var code = fs.readFileSync(file, "utf8"),
+			locs = locater.find("o.only", code);
+
+		locs.forEach((loc) =>
+			fail(dedent(`
+				${link(file, `#L${loc.line}`)} is preventing tests from running.
+				<pre lang="javascript">
+				${pinpoint(code, {line: loc.line, column : loc.cursor})}
+				</pre>
+			`))
+		)
+	});

package.json

@@ -11,6 +11,7 @@
     "build": "npm run build-browser & npm run build-min",
     "build-browser": "node bundler/cli browser.js -output mithril.js",
     "build-min": "node bundler/cli browser.js -output mithril.min.js -minify",
+    "danger": "danger",
     "lintdocs": "node docs/lint",
     "gendocs": "node docs/generate",
     "lint": "eslint . || true",
@@ -26,9 +27,13 @@
   },
   "devDependencies": {
     "benchmark": "^2.1.4",
+    "danger": "^1.0.0",
+    "dedent": "^0.7.0",
     "eslint": "^3.19.0",
     "istanbul": "^0.4.5",
-    "marked": "^0.3.6"
+    "locater": "^1.3.0",
+    "marked": "^0.3.6",
+    "pinpoint": "^1.1.0"
   },
   "bin": {
     "ospec": "./ospec/bin/ospec"