screenshot css element using puppeteer

readme.md

node screenshot.js --fetchUrl=http://localhost/urlhere --cssSelector=.submission-result --writeToFile=./cache/filename.png

package.json

{
    "private": true,
    "scripts": {},
    "dependencies": {
        "axios": "^0.17",
        "jquery": "^3.2",
        "lodash": "^4.17.4",
        "puppeteer": "^1.0.0",
        "command-line-args": "^5.0.1",
        "command-line-usage": "^4.1.0"
    }
}

screenshot.js

const puppeteer = require('puppeteer');
const CommandLineArgs  = require('command-line-args');
const CommandLineUsage = require('command-line-usage');

const usage = CommandLineUsage([
    {
        header: 'Options',
        optionList: [
            {
                name: 'fetchUrl',
                description: 'http url path'
            },
            {
                name: 'cssSelector',
                description: 'markup-path'
            },
            {
                name: 'writeToFile',
                description: 'markup-path'
            },
            {
                name: 'help',
                description: 'Print this usage guide.'
            }
        ]
    }
]);

let options = null;

try{
     options = CommandLineArgs([
        { name: 'fetchUrl', type: String },
        { name: 'cssSelector', type: String },
        { name: 'writeToFile', type: String },
        { name: 'help', type: String},
    ]);
}
catch(e)
{
    console.log('Invalid field', e.message);
    console.info(usage);
    return;
}

if('help' in options)
{
    console.info(usage);
    return;
}

for(let field of ['fetchUrl', 'cssSelector', 'writeToFile'])
{
    if(false === (field in options))
    {
        console.info(usage);
        return 1;
    }
}

(async () => {
    const browser = await puppeteer.launch({args: ['--no-sandbox']});
    const page = await browser.newPage();
    await page.setViewport({width: 1920, height: 1080});
    await page.goto(options['fetchUrl']);

    await page.waitFor(1000);
    try
    {
        let item = await page.$(options['cssSelector']);
        item.screenshot({
            path:options['writeToFile']
        })
            .then(res=>{
                console.log({
                    path:options['writeToFile']
                });
                browser.close();
            })
            .catch(err=>{
                console.error(err);
                browser.close();
            });
    }catch(e){
        console.log(e);
        browser.close();
    }
})();