added pluggable functionality

examples/pluggable.js

@@ -0,0 +1,39 @@
+module.exports = {
+    get_browser: get_browser,
+    handle_metadata: handle_metadata,
+    close_browser: close_browser
+};
+
+async function close_browser(browser) {
+    await browser.close();
+}
+
+async function handle_metadata() {
+    // silence
+}
+
+async function get_browser(launch_args) {
+    const puppeteer = require('puppeteer');
+
+    const ADDITIONAL_CHROME_FLAGS = [
+        '--no-sandbox',
+        '--disable-setuid-sandbox',
+        '--disable-dev-shm-usage',
+        '--disable-accelerated-2d-canvas',
+        '--disable-gpu',
+        '--window-size=1920x1080',
+        '--hide-scrollbars',
+        '--user-agent=Chrome',
+    ];
+
+    let custom_args = {
+        args: ADDITIONAL_CHROME_FLAGS,
+        headless: true,
+    };
+
+    browser = await puppeteer.launch(launch_args);
+
+    console.log('Loaded custom function get_browser()');
+
+    return browser;
+}