chore: add automatic github release (#4466)

This will automatically do a github release with the correct changelog entry and the built zip file.
If a publish is made with `--tag next` it will mark the release as a pre-release.

To use, just add `VJS_GITHUB_USER` and `VJS_GITHUB_TOKEN` env variables as part of the publish command:
```sh
$ VJS_GITHUB_USER=gkatsev VJS_GITHUB_TOKEN=test_token npm publish --tag next
```

build/current-changelog.js

@@ -0,0 +1,33 @@
+var unified = require('unified');
+var markdown = require('remark-parse');
+var stringify = require('remark-stringify');
+var fs = require('fs');
+
+module.exports = function() {
+  var processor = unified()
+  .use(markdown, {commonmark: true})
+  .use(stringify);
+
+  var ast = processor.parse(fs.readFileSync('./CHANGELOG.md'));
+
+  var changelog = [];
+  changelog.push(processor.stringify(ast.children[0]));
+
+  // start at 1 so we get the first anchor tag
+  // and can break on the second
+  for (var i = 1; i < ast.children.length; i++) {
+    var item = processor.stringify(ast.children[i]);
+
+    if (/^<a name="/.test(item)) {
+      break;
+    }
+
+    if (/^###/.test(item)) {
+      item = '\n' + item + '\n';
+    }
+
+    changelog.push(item);
+  }
+
+  return changelog.join('\n');
+};

build/gh-release.js

@@ -0,0 +1,33 @@
+var ghrelease = require('gh-release');
+var currentChangelog = require('./current-changelog.js');
+var safeParse = require('safe-json-parse/tuple');
+var pkg = require('../package.json')
+
+var options = {
+  owner: 'videojs',
+  repo: 'video.js',
+  body: currentChangelog(),
+  assets: ['./dist/videojs-'+pkg.version+'.zip'],
+  endpoint: 'https://api.github.com',
+  auth: {
+    username: process.env.VJS_GITHUB_USER,
+    password: process.env.VJS_GITHUB_TOKEN
+  }
+};
+
+var tuple = safeParse(process.env.npm_config_argv);
+var npmargs = tuple[0] ? [] : tuple[1].cooked;
+
+if (npmargs.some(function(arg) { return /next/.test(arg); })) {
+  options.prerelease = true;
+}
+
+ghrelease(options, function(err, result) {
+  if (err) {
+    console.log('Unable to publish release to github');
+    console.log(err);
+  } else {
+    console.log('Publish release to github!');
+    console.log(result);
+  }
+});

package.json

@@ -39,6 +39,7 @@
     "docs:fix": "remark --output -- './**/*.md'",
     "babel": "babel src/js -d es5",
     "prepublish": "not-in-install && run-p docs:api build || in-install",
+    "publish": "node build/gh-release.js",
     "prepush": "npm run lint -- --errors",
     "version": "node build/version.js && git add CHANGELOG.md"
   },
@@ -78,6 +79,7 @@
     "es5-shim": "^4.1.3",
     "es6-shim": "^0.35.1",
     "filesize": "^3.5.6",
+    "gh-release": "^3.0.0",
     "grunt": "^0.4.5",
     "grunt-accessibility": "^5.0.0",
     "grunt-babel": "^6.0.0",
@@ -129,6 +131,8 @@
     "qunitjs": "1.23.1",
     "remark-cli": "^3.0.0",
     "remark-lint": "^6.0.0",
+    "remark-parse": "^3.0.1",
+    "remark-stringify": "^3.0.1",
     "remark-toc": "^4.0.0",
     "remark-validate-links": "^6.0.0",
     "replace": "^0.3.0",
@@ -147,6 +151,7 @@
     "time-grunt": "^1.1.1",
     "tui-jsdoc-template": "^1.1.0",
     "uglify-js": "~2.8.8",
+    "unified": "^6.1.5",
     "videojs-doc-generator": "0.0.1",
     "videojs-flash": "^2.0.0",
     "videojs-standard": "^6.0.1",