Getting TypeError: selector.includes is not a function when scraping with cheerio and jsonframe

Question

I am trying to scrap a website with the following code:

const cheerio = require('cheerio');
const jsonframe = require('jsonframe-cheerio');

const $ = cheerio.load('https://coinmarketcap.com/all/views/all/');
jsonframe($); // initializes the plugin

//exception handling 
process.on('uncaughtException', err =>
  console.error('uncaught exception: ', err))
process.on('unhandledRejection', (reason, p) =>
  console.error('unhandled rejection: ', reason, p))

const frame = {
    "crypto": {         
        "selector": "tbody > tr",   
        "data": [{             
            "name": "td:nth-child(2) > a:nth-child(3)", 
            "url": {                                  
                "selector": "td:nth-child(2) > a:nth-child(3)",    
                "attr": "href"                     
            },
            "marketcap": "tr > td:nth-child(4)",
            "price": "tr > td:nth-child(5) > a:nth-child(1)", 
        }]
    }

};

let companiesList = $('tbody').scrape(frame);
console.log(companiesList); 

However, I get an UnhandledPromiseRejectionWarning when running the above example code:

(node:3890) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: selector.includes is not a function

Any suggestions what I am doing wrong?

I appreciate your replies!

UPDATE

I changed my code to the following below. However, I only can scrap the first element.

Any suggestions why the other elements do not get scrapped?

const cheerio = require('cheerio')
const jsonframe = require('jsonframe-cheerio')
const got = require('got');


async function scrapCoinmarketCap() {
    const url = 'https://coinmarketcap.com/all/views/all/'
    const html = await got(url)
    const $ = cheerio.load(html.body)

    jsonframe($) // initializing the plugin

    let frame = {
        "Coin": "td.no-wrap.currency-name > a",
        "url": "td.no-wrap.currency-name > a @ href",
        "Symbol": "td.text-left.col-symbol",
        "Price": "td:nth-child(5) > a",
    }

    console.log($('body').scrape(frame, {
        string: true
    }))
}

scrapCoinmarketCap()

Answer 1

Based on your updated code, you can scrape all currency data by iterating on each tr:

$('body tr').each(function() {
  console.log($(this).scrape(frame, {
    string: true
  }))
})

However, I think the cleanest way to do this (as I said in another answer) is to use jsonframe-cheerio List/Array frame pattern, which is exactly intended to do that:

let frame = {
  currency: {
    _s: "tr",  // the selector
    _d: [{  // allow you to get an array of data, not just the first item
      "Coin": "td.no-wrap.currency-name > a",
      "Url": "td.no-wrap.currency-name > a @ href",
      "Symbol": "td.text-left.col-symbol",
      "Price": "td:nth-child(5) > a"
    }]
  }
}

console.log($('body').scrape(frame, {
  string: true
}))