Use rxjs observables for blockchain data

src/gasAlertChecker.ts

@@ -0,0 +1,42 @@
+import { EmbedBuilder, TextChannel } from 'discord.js';
+
+import { DiscordClient } from './discordClient';
+import redisClient from './redis';
+
+import { GasAlert } from '../types/gasAlert';
+import { GasPrices } from '../types/gasPrices';
+
+const createGasAlertChecker = (client: DiscordClient) => 
+  async (gasPrices: GasPrices) => {
+    try {
+      const gasAlerts: GasAlert[] = await redisClient
+        .hVals('gas-alerts')
+        .then((values) => values.map(val => JSON.parse(val)));
+
+      gasAlerts.forEach(async (gasAlert) => {
+        if (gasPrices.fast <= gasAlert.threshold) {
+          const channel = await client.channels.fetch(gasAlert.channelId) as TextChannel;
+          const user = await client.users.fetch(gasAlert.userId);
+
+          channel.send({
+            embeds: [
+              new EmbedBuilder()
+                .setTitle('Gas price alert!')
+                .setDescription(`<@${gasAlert.userId}>!
+Gas prices have fallen below your alert threshold of ${gasAlert.threshold} Gwei:
+⚡ ${gasPrices.fast} ⦚⦚ 🚶 ${gasPrices.average} ⦚⦚ 🐢 ${gasPrices.slow}`)
+                .setColor('#FF8C00')
+            ],
+            target: user
+          })
+
+          console.log(`Alerted ${user} under threshold ${gasAlert.threshold}: Removing alert...`)
+          await redisClient.hDel('gas-alerts', `${gasAlert.userId}`)
+        }
+      });
+    } catch (error) {
+      console.log(`Error checking gas prices:\n`, error);
+    }
+  };
+
+export { createGasAlertChecker };