sending notification when new items arrive with send grid

backend/utils/arethereanynewitems.js

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+const convertToDate = require("./convertToDate");
+function areThereAnyNewItems(lastItemDate, controlDate) {
+  if (!lastItemDate) {
+    return true;
+  }
+  return new Date(controlDate) < convertToDate(lastItemDate);
+}
+module.exports = areThereAnyNewItems;

backend/utils/convertToDate.js

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+function convertToDate(date) {
+  const [dan, mjesec, godina] = date
+    .split(". u ")[0]
+    .split(".")
+    .map(el => Number(el));
+  const [sati, minute] = date
+    .split(". u ")[1]
+    .split(":")
+    .map(el => Number(el));
+  return new Date(godina, mjesec, dan, sati, minute);
+}
+
+module.exports = convertToDate;

backend/utils/scraptheitems.js

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+let fetch = require("node-fetch");
+let cheerio = require("cheerio");
+const areThereAnyNewItems = require("./arethereanynewitems");
+
+async function scrapTheItems(url, controlDate, noNewItems = false) {
+  let items = [];
+  let response = await fetch(url);
+  const body = await response.text();
+  const $ = cheerio.load(body);
+  $("#rezultatipretrage")
+    .find(".listitem")
+    .each(async (index, elem) => {
+      if (noNewItems) return;
+      const itemDate = $(elem)
+        .find(".cijena > .datum > div")
+        .first()
+        .attr("data-cijelidatum");
+
+      if (controlDate && !areThereAnyNewItems(itemDate, controlDate)) {
+        noNewItems = true;
+        return;
+      }
+
+      const id = $(elem)
+        .find("a")
+        .first()
+        .attr("href");
+      const cijena = $(elem)
+        .find(".cijena > .datum > span")
+        .first()
+        .text();
+      const image = $(elem)
+        .find("a > .slika > img")
+        .first()
+        .attr("src");
+
+      items.push({ url: id, price: cijena, image, date: itemDate });
+    });
+  return items;
+}
+
+module.exports = scrapTheItems;

backend/utils/sendnotification.js

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+const scrapTheItems = require("./scraptheitems");
+const convertToDate = require("./convertToDate");
+const sgMail = require("@sendgrid/mail");
+// should be process.env.SENDGRID_API_KEY
+sgMail.setApiKey(
+  "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"
+);
+
+async function sendNotification(marketAlert) {
+  const { id, email, olx_url, last_date } = marketAlert;
+  let url =
+    "https://www.olx.ba/pretraga?" + olx_url + "&sort_order=desc&sort_po=datum";
+  let newItems = await scrapTheItems(url);
+  let lastDate = newItems.length && newItems[0].date;
+  let message =
+    newItems.length &&
+    newItems.reduce(
+      (mes, item) => mes + `<strong>${item.url} i  ${item.price}</strong>`,
+      ""
+    );
+  const msg = {
+    to: email,
+    from: "test@example.com",
+    subject: "Market Alert",
+    text: "New items on olx",
+    html: message
+  };
+  if (message) {
+    await sgMail.send(msg);
+    return { id, date: String(convertToDate(lastDate)) };
+  }
+}
+module.exports = sendNotification;