Add Dangerfile and provide bundle size info

.github/workflows/danger.yml

@@ -0,0 +1,20 @@
+name: Danger
+
+on: 
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  run:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+        with:
+          fetch-depth: 0
+      - run: npm ci
+      - name: Danger
+        run: npx danger ci
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.npmignore

@@ -13,6 +13,7 @@ tests/
 *.html
 bower.json
 composer.json
+dangerfile.js
 gulpfile.js
 .editorconfig
 .gitattributes

dangerfile.js

@@ -0,0 +1,114 @@
+const { markdown } = require('danger');
+const fs = require('fs').promises;
+const gzipSize = require('gzip-size');
+const git = require('simple-git/promise')(__dirname).silent(true);
+
+// https://stackoverflow.com/questions/15900485/correct-way-to-convert-size-in-bytes-to-kb-mb-gb-in-javascript
+const formatBytes = (bytes, decimals = 2) => {
+	if (bytes === 0) return '0 Bytes';
+
+	const k = 1000;
+	const dm = decimals < 0 ? 0 : decimals;
+	const sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
+
+	const i = Math.floor(Math.log(Math.abs(bytes)) / Math.log(k));
+
+	return parseFloat((bytes / Math.pow(k, i)).toFixed(dm)) + ' ' + sizes[i];
+}
+
+const maybePlus = (from, to) => from < to ? "+" : "";
+
+const absDiff = (from, to) => {
+	if (from === to) {
+		return formatBytes(0);
+	}
+
+	return `${maybePlus(from, to)}${formatBytes(to - from)}`;
+}
+
+const percDiff =  (from, to) => {
+	if (from === to) {
+		return '0%';
+	}
+
+	return `${maybePlus(from, to)}${
+		(100 * (to - from) / (from || to)).toFixed(1)
+	}%`;
+}
+
+const getSummary = (rows, totalMasterFileSize, totalFileSize) => {
+	const numFiles = rows.length;
+	const maybeS = rows.length > 0 ? 's' : '';
+	const byteDiff = absDiff(totalMasterFileSize, totalFileSize);
+	const percentDiff = percDiff(totalMasterFileSize, totalFileSize);
+
+	return `A total of ${numFiles} file${maybeS} have changed, with a combined diff of ${byteDiff} (${percentDiff}).`;
+}
+
+const getChangedMinifiedFiles = async () => {
+	const result = await git.diff(['--name-only', '--no-renames', 'master...']);
+
+	return result
+		? result.split(/\r?\n/g).filter(file => file.endsWith('.min.js'))
+		: [];
+};
+
+const run = async () => {
+	// Check if master exists & check it out if not.
+	const result = await git.branch(['--list', 'master']);
+	if (result.all.length === 0) {
+		await git.branch(['master', 'origin/master']);
+	}
+
+	const minified = await getChangedMinifiedFiles();
+
+	if (minified.length === 0) {
+		markdown(`## No JS Changes`);
+		return;
+	}
+
+	const rows = [];
+	let totalFileSize = 0;
+	let totalMasterFileSize = 0;
+
+	for (const file of minified) {
+		const [fileContents, fileMasterContents] = await Promise.all([
+			fs.readFile(file, 'utf-8').catch(() => ''),
+			git.show([`master:${file}`]).catch(() => ''),
+		]);
+
+		const [fileSize, fileMasterSize] = await Promise.all([
+			gzipSize(fileContents),
+			gzipSize(fileMasterContents),
+		]);
+
+		totalFileSize += fileSize;
+		totalMasterFileSize +=fileMasterSize
+
+		rows.push([
+			file,
+			formatBytes(fileMasterSize),
+			formatBytes(fileSize),
+			absDiff(fileMasterSize, fileSize),
+			percDiff(fileMasterSize, fileSize),
+		]);
+	}
+
+	markdown(`## JS File Size Changes (gzipped)
+
+${getSummary(rows, totalMasterFileSize, totalFileSize)}
+
+<details>
+
+| file | master | pull | size diff | % diff |
+| --- | --- | --- | --- | --- |
+${rows.map(row => `| ${row.join(' | ')} |`).join('\n')}
+
+</details>
+`);
+}
+
+run().catch(err => {
+	console.error(err);
+	process.exit(1);
+});