Q:

How to handle puppeteer exception on synchronous execution

I am trying to achieve a synchronous call:
puppeteer.launch().then(browser => {
            let html = `
            <!DOCTYPE html>
            <html>
               <body>
                 <div>
                    Hello
                 </div>
              </body>
            </html>
            `;

            let path = 'test.png';

            browser.newPage().then(page => {
                page.setContent(html).then(() => {
                    page
                        .screenshot({
                            path: path,
                            clip: {
                                x: 50,
                                y: 50,
                                width: 100,
                                height: 100
                            },
                            omitBackground: true
                        })
                        .then(() => {});
                });
            });
            browser.close().then(() => {});
        });

I get the following exception:
(node:22140) UnhandledPromiseRejectionWarning: Error: Protocol error (Target.createTarget): Target closed.
    at Promise (C:\ImageServer\node_modules\puppeteer\lib\Connection.js:74:56)
    at new Promise ()
    at Connection.send (C:\ImageServer\node_modules\puppeteer\lib\Connection.js:73:12)
    at Browser._createPageInContext (C:\ImageServer\node_modules\puppeteer\lib\Browser.js:174:47)
    at BrowserContext.newPage (C:\ImageServer\node_modules\puppeteer\lib\Browser.js:367:26)
    at Browser.newPage (C:\ImageServer\node_modules\puppeteer\lib\Browser.js:166:33)
    at Browser. (C:\ImageServer\node_modules\puppeteer\lib\helper.js:112:23)
    at puppeteer.launch.then.browser (C:\ImageServer\imageServer.js:48:12)
    at process._tickCallback (internal/process/next_tick.js:68:7)
(node:22140) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:22140) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
How do I fix this?

A:

The problem is that you are closing the browser right after browser.newPage. You should move browser.close() to the then you have for screenshot.
page
    .screenshot({
        path: path,
        clip: {
            x: 50,
            y: 50,
            width: 100,
            height: 100
        },
        omitBackground: true
    })
    .then(() => browser.close());

