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JavaScript

Ryan Morales
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Ryan Morales
Full Stack JavaScript Techdegree Graduate 33,933 Points
Posted by Ryan Morales
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Ryan Morales
Full Stack JavaScript Techdegree Graduate 33,933 Points

Using promises and promise all with asynchronous calls to return an array of data.

I am attempting to scrape product urls from a page then use those urls to visit each products page and scrape information for the products. I am trying to create a Promise chain but I'm a beginner with Promises. The hang up is trying to return the product prices as an array after visiting each product url. Right now my code is just returning an array of undefined values. I have tried many combinations of for loops, prototype map, promises and Promise all. I can't figure it out. Any help would be appreciated. code below:

const request = require('request');
const cheerio = require('cheerio');
const fs = require('fs');
const rp = require('request-promise');

// Thanks to chovy @ stack overflow 
//https://stackoverflow.com/questions/21194934/node-how-to-create-a-directory-if-doesnt-exist
if (!fs.existsSync("./data")) {
    fs.mkdirSync("./data");
}

let shirturlscrape = new Promise((resolve) => {
    let mikeshirturl = 'http://www.shirts4mike.com/shirts.php';
    request(mikeshirturl, (error, response, html) => {
        if (!error) {
            const $ = cheerio.load(html);
            let shirtlinks = [];
            $('.products').filter(function() {
                let data = $(this);
                data.find('li a').each(function(i) {
                    shirtlinks.push($(this).attr('href'));
                });
                let shirturls = [];
                shirtlinks.map((i) => {
                    let url = 'http://www.shirts4mike.com/' + i;
                    shirturls.push(url);
                }) // end shirtlink map
                resolve(shirturls);
            }) // end products filter
        } // end error check
    }); // end request url

});

let shirtPrices = [];
let getPrices = (html) => {
    return new Promise((resolve)=>{
      const $ = cheerio.load(html);
        $('.shirt-details').filter(function(){
            let data = $(this);
            let price = data.find('.price').text();
            resolve(price);
        })  
    })

}


shirturlscrape
    .then((result)=>{
        Promise.all(result.map((i)=>{
            rp(i)
            .then(getPrices)
        }))
        .then((result)=>{
            console.log(result)
        })

})

1 Answer