Hackernoon logoScraping Tesla Stock Prices with Node.js and Puppeteer by@codejedi

Scraping Tesla Stock Prices with Node.js and Puppeteer

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@codejediCode_Jedi

Python, Machine Learning, Web-Scraping, Web-Automation and more...

Hey, fellow devs 👋

In this tutorial, I will be showing you guys how to scrape the latest Tesla stock prices using Node.js and puppeteer.

Let’s get started!

First of all, you will need to install the puppeteer using

npm i puppeteer
. Now if you don’t have
npm
,
package.json
, and
node_modules setup
, here’s a great tutorial.

After you’ve installed puppeteer, create a new javascript file and require puppeteer on the first line:

const puppeteer = require('puppeteer');

Then create the async function in which we are going to write our main code:

const puppeteer = require('puppeteer');
async function start() {
}
start();

Now we’re ready to start scraping.

First of all, you need to initiate a new browser instance, as well as define the url which your web-scraper is going to be visiting:

const puppeteer = require('puppeteer');
async function start() {
  const url = 'https://finance.yahoo.com/quote/TSLA?p=TSLA&.tsrc=fin-srch';
  const browser = await puppeteer.launch({
    headless: false
  });
}

Next, you need to call the

newPage()
function to open a new page in the browser, and go to the url that we defined using the
goto()
function:

const puppeteer = require('puppeteer');
async function start() {
  const url = 'https://finance.yahoo.com/quote/TSLA?p=TSLA&.tsrc=fin-srch';
  const browser = await puppeteer.launch({
    headless: false
  });
  const page = await browser.newPage();
  await page.goto(url);
}

For this next step, you will have to go to https://finance.yahoo.com/quote/TSLA?p=TSLA&.tsrc=fin-srch, right-click on the current stock price, and click on inspect:

image

A pop-up will appear on the right of your window, you will need to find the stock price element:

image

Next, you will need to right-click on the stock price element and click on “copy full Xpath”.
This will give us a way of accessing the stock price element:

image

Once we have the Xpath of the stock price element, we can add these 3 lines of code into our function:

var element = await page.waitForXPath("put the stock price Xpath here")
  var price = await page.evaluate(element => element.textContent, element);
  console.log(price);

The

page.waitForXPath()
function will locate the stock price element.
Next, the
page.evaluate
function will get the text contents of the stock price element which would then be printed by the
console.log()
function.

At this point, your code should look something like this:

const puppeteer = require('puppeteer');
async function start() {
  const url = 'https://finance.yahoo.com/quote/TSLA?p=TSLA&.tsrc=fin-srch';
  const browser = await puppeteer.launch({
    headless: false
  });
  const page = await browser.newPage();
  await page.goto(url);
  var element = await page.waitForXPath("/html/body/div[1]/div/div/div[1]/div/div[2]/div/div/div[5]/div/div/div/div[3]/div[1]/div[1]/span[1]")
  var price = await page.evaluate(element => element.textContent, element);
  console.log(price);
}
start()

If you were to execute your current code, you will find that when going to the url that you defined earlier, a pop-up will appear:

image

To get around this, plug these 2 lines of code into your function before defining the “element” variable:

var accept = ("#consent-page > div > div > div > form > div.wizard-body > div.actions.couple > button");
await page.click(accept)

This will locate the “Accept All” button and click it to make the popup go away.

Now you will have a working function that goes to your defined url, scrapes the latest Tesla stock price, and prints it in your terminal.

To go one step further, you can put these lines of code in a for loop:

for(var k = 1; k < 2000; k++){
      var element = await page.waitForXPath("/html/body/div[1]/div/div/div[1]/div/div[2]/div/div/div[5]/div/div/div/div[3]/div[1]/div[1]/span[1]")
      var price = await page.evaluate(element => element.textContent, element);
      console.log(price);
      await page.waitForTimeout(1000);
    }

The

page.waitForTimeout(1000)
function will wait 1000 milliseconds(1 second) before repeating the for a loop.

And finally,

add a browser.close()
function after the for loop to close the browser and finish your code execution:

const puppeteer = require('puppeteer');
async function start() {
    const url = 'https://finance.yahoo.com/quote/TSLA?p=TSLA&.tsrc=fin-srch';
    const browser = await puppeteer.launch({
      headless: false
    });  
    const page = await browser.newPage();
    await page.goto(url);
    var accept = ("#consent-page > div > div > div > form > div.wizard-body > div.actions.couple > button");
    await page.click(accept);
    for(var k = 1; k < 2000; k++){
      var element = await page.waitForXPath("/html/body/div[1]/div/div/div[1]/div/div[2]/div/div/div[5]/div/div/div/div[3]/div[1]/div[1]/span[1]");
      var price = await page.evaluate(element => element.textContent, element);
      console.log(price);
      await page.waitForTimeout(1000);
    }
    browser.close();
}
start();

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