Add Client

client/index.js

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+const io = require('socket.io-client');
+const socket = io('http://localhost:3000');
+
+let timeFlag; // Flag to keep track of time passed
+let prevData; // Object to store and compare previously sent data
+
+socket.on('connect', () => {
+    console.log('Connected to server!'); // Client connects to server
+
+    // Only happens the first time the client connects to the server
+    timeFlag = new Date();
+    prevData = {
+        temperature: getTemp(),
+        humAir: getHumAir(),
+        humGround: getHumGround(),
+        airSpeed: getAirSpeed(),
+    }
+});
+
+setInterval(() => {
+    let data = {
+        temperature: getTemp(),
+        humAir: getHumAir(),
+        humGround: getHumGround(),
+        airSpeed: getAirSpeed(),
+    }
+
+    const now = new Date();
+    let timeDiff = now - timeFlag;
+    timeDiff /= 1000;
+
+    // If more than 5 minutes have passed or compareData is true
+    if ((timeDiff > 5) || compareData(data)) {
+        prevData = data;
+        timeFlag = new Date();
+        socket.emit('data', data);
+    }
+}, 2 * 1000); // Every 30s
+
+// Return a test temp from 1-50
+getTemp = () => {
+    return Math.floor(Math.random() * 50);
+}
+
+// Return a test air humidity from 1-100
+getHumAir = () => {
+    return Math.floor(Math.random() * 100);
+}
+
+// Return a test ground humidity from 1-100
+getHumGround = () => {
+    return Math.floor(Math.random() * 100);
+}
+
+// Return a test wind speed from 1-12
+getAirSpeed = () => {
+    return Math.floor(Math.random() * 12);
+}
+
+// Compare data with prevData and determine if they need to be send to server
+compareData = (data) => {
+    for (const key in data) {
+        if (diff(data[key], prevData[key]) > 10)
+            return true;
+    }
+    return false;
+}
+
+// Handy function to calculate the % difference
+diff = (x, y) => {
+    return 100 * Math.abs((x - y) / ((x + y) / 2));
+}

client/package.json

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+{
+  "name": "client",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "run": "node index.js",
+    "dev": "nodemon index.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "nodemon": "^2.0.7",
+    "socket.io-client": "^3.1.0"
+  }
+}