Scrape single column from table on Wikipedia using NodeJS Cheerio - node.js

Question

I am trying to scrape a column from the table located on Wikipedia. I am trying to get the first column, Symbol, and use those symbols in an array in NodeJS. I attempted to scrape only this column using Cheerio and Axios. For some reason, after running the function I do not get any syntax errors but I also do not get any result after execution. I'm not sure if the elements I have loaded are correct or not, but any advice on how I can scrape the Symbol column into an array would be helpful. Below is my code:
const express = require('express');
const app = express();
const http = require('http');
const server = http.createServer(app);
const cheerio = require('cheerio');
const axios = require("axios");
async function read_fortune_500() {
try {
const url = 'https://en.wikipedia.org/wiki/List_of_S%26P_500_companies'
const { data } = await axios({
method: "GET",
url: url,
})
const $ = cheerio.load(data)
const elemSelector = '#constituents > tbody > tr:nth-child(1) > td'
$(elemSelector).each((parentIndex, parentElem) => {
if (parentIndex <= 9){
$(parentElem).children().each((childIndex, childElem) => {
console.log($(childElem).text())
})
}
})
} catch (err) {
console.error(err)
}
}
read_fortune_500()
Result
[Finished in 1.238s]

Answer 1

To help with your original issue:
For some reason, after running the function I do not get any syntax
errors but I also do not get any result after execution.
The reason for this is that you are calling an async function in javascript. Because read_fortune_500 has the async keyword, you need to 'wait' for this function to complete. In javascript world, the read_fortune_500 is actually returning a promise and you need to wait until the promise resolves. You can do that in a couple of ways:
The easiest way to handle this is tp wrap your function call inside an IIFE:
(async () => {
await read_fortune_500()
})();
In future versions of node you can use await without the need for wrapping it but hopefully that helps.
For the second issue, getting a list of symbols. You need to update the query selector you are using:
const $ = cheerio.load(data)
const elements = $("#constituents > tbody > tr > td:nth-child(1)")
elements.each((parentIndex, parentElem) => {
The CSS selector is slightly different but the selector above tells cheerio to look inside each table row in the DOM and then select the first column in that row.
Full working code below:
const cheerio = require('cheerio');
const axios = require("axios");
async function read_fortune_500() {
try {
const url = 'https://en.wikipedia.org/wiki/List_of_S%26P_500_companies'
const { data } = await axios({
method: "GET",
url: url,
})
const $ = cheerio.load(data)
const elements = $("#constituents > tbody > tr > td:nth-child(1)")
elements.each((parentIndex, parentElem) => {
if (parentIndex <= 9){
$(parentElem).children().each((childIndex, childElem) => {
console.log($(childElem).text())
})
}
})
} catch (err) {
console.error(err)
}
}
(async () => {
await read_fortune_500()
})();