improvement: adopted infinity scroll in users and contacts

backend/src/controllers/UserController.js

@@ -7,7 +7,7 @@ const User = require("../models/User");
 const { getIO } = require("../libs/socket");
 
 exports.index = async (req, res) => {
-	const { searchParam = "", pageNumber = 1, rowsPerPage = 10 } = req.query;
+	const { searchParam = "", pageNumber = 1 } = req.query;
 
 	const whereCondition = {
 		[Op.or]: [
@@ -22,7 +22,7 @@ exports.index = async (req, res) => {
 		],
 	};
 
-	let limit = +rowsPerPage;
+	let limit = 20;
 	let offset = limit * (pageNumber - 1);
 
 	const { count, rows: users } = await User.findAndCountAll({
@@ -33,7 +33,9 @@ exports.index = async (req, res) => {
 		order: [["createdAt", "DESC"]],
 	});
 
-	return res.status(200).json({ users, count });
+	const hasMore = count > offset + users.length;
+
+	return res.status(200).json({ users, count, hasMore });
 };
 
 exports.store = async (req, res, next) => {

frontend/src/pages/Contacts/index.js

@@ -47,25 +47,22 @@ const reducer = (state, action) => {
 		return [...state, ...newContacts];
 	}
 
-	if (action.type === "UPDATE_CONTACT") {
+	if (action.type === "UPDATE_CONTACTS") {
-		const updatedContact = action.payload;
+		const contact = action.payload;
-		const contactIndex = state.findIndex(c => c.id === updatedContact.id);
+		const contactIndex = state.findIndex(c => c.id === contact.id);
 
 		if (contactIndex !== -1) {
-			state[contactIndex] = updatedContact;
+			state[contactIndex] = contact;
 		}
 
-		return [...state];
+		return [contact, ...state];
 	}
 
 	if (action.type === "DELETE_CONTACT") {
 		const contactId = action.payload;
-		console.log("cai aqui", contactId);
 
 		const contactIndex = state.findIndex(c => c.id === contactId);
 		if (contactIndex !== -1) {
-			console.log("cai no if");
-
 			state.splice(contactIndex, 1);
 		}
 		return [...state];
@@ -119,7 +116,7 @@ const Contacts = () => {
 		const socket = openSocket(process.env.REACT_APP_BACKEND_URL);
 		socket.on("contact", data => {
 			if (data.action === "update" || data.action === "create") {
-				dispatch({ type: "UPDATE_CONTACT", payload: data.contact });
+				dispatch({ type: "UPDATE_CONTACTS", payload: data.contact });
 			}
 
 			if (data.action === "delete") {

frontend/src/pages/Users/index.js

@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from "react";
+import React, { useState, useEffect, useReducer } from "react";
 
 import openSocket from "socket.io-client";
 
@@ -28,6 +28,45 @@ import TableRowSkeleton from "../../components/TableRowSkeleton";
 import UserModal from "../../components/UserModal";
 import ConfirmationModal from "../../components/ConfirmationModal";
 
+const reducer = (state, action) => {
+	if (action.type === "LOAD_USERS") {
+		const users = action.payload;
+		const newUsers = [];
+
+		users.forEach(user => {
+			const userIndex = state.findIndex(u => u.id === user.id);
+			if (userIndex !== -1) {
+				state[userIndex] = user;
+			} else {
+				newUsers.push(user);
+			}
+		});
+
+		return [...state, ...newUsers];
+	}
+
+	if (action.type === "UPDATE_USERS") {
+		const user = action.payload;
+		const userIndex = state.findIndex(u => u.id === user.id);
+
+		if (userIndex !== -1) {
+			state[userIndex] = user;
+		}
+
+		return [user, ...state];
+	}
+
+	if (action.type === "DELETE_USER") {
+		const userId = action.payload;
+
+		const userIndex = state.findIndex(u => u.id === userId);
+		if (userIndex !== -1) {
+			state.splice(userIndex, 1);
+		}
+		return [...state];
+	}
+};
+
 const useStyles = makeStyles(theme => ({
 	mainPaper: {
 		flex: 1,
@@ -42,22 +81,24 @@ const Users = () => {
 
 	const [loading, setLoading] = useState(false);
 	const [pageNumber, setPageNumber] = useState(1);
+	const [hasMore, setHasMore] = useState(false);
 	const [selectedUserId, setSelectedUserId] = useState(null);
 	const [userModalOpen, setUserModalOpen] = useState(false);
 	const [confirmModalOpen, setConfirmModalOpen] = useState(false);
 	const [deletingUser, setDeletingUser] = useState(null);
 	const [searchParam, setSearchParam] = useState("");
-	const [users, setUsers] = useState([]);
+	const [users, dispatch] = useReducer(reducer, []);
 
 	useEffect(() => {
 		setLoading(true);
 		const delayDebounceFn = setTimeout(() => {
 			const fetchUsers = async () => {
 				try {
-					const res = await api.get("/users/", {
+					const { data } = await api.get("/users/", {
 						params: { searchParam, pageNumber },
 					});
-					setUsers(res.data.users);
+					dispatch({ type: "LOAD_USERS", payload: data.users });
+					setHasMore(data.hasMore);
 					setLoading(false);
 				} catch (err) {
 					console.log(err);
@@ -73,11 +114,11 @@ const Users = () => {
 		const socket = openSocket(process.env.REACT_APP_BACKEND_URL);
 		socket.on("user", data => {
 			if (data.action === "update" || data.action === "create") {
-				updateUsers(data.user);
+				dispatch({ type: "UPDATE_USERS", payload: data.user });
 			}
 
 			if (data.action === "delete") {
-				deleteUser(data.userId);
+				dispatch({ type: "DELETE_USER", payload: +data.userId });
 			}
 		});
 
@@ -86,31 +127,6 @@ const Users = () => {
 		};
 	}, []);
 
-	const updateUsers = user => {
-		setUsers(prevState => {
-			const userIndex = prevState.findIndex(c => c.id === user.id);
-
-			if (userIndex === -1) {
-				return [user, ...prevState];
-			}
-			const aux = [...prevState];
-			aux[userIndex] = user;
-			return aux;
-		});
-	};
-
-	const deleteUser = userId => {
-		setUsers(prevState => {
-			const userIndex = prevState.findIndex(c => c.id === +userId);
-
-			if (userIndex === -1) return prevState;
-
-			const aux = [...prevState];
-			aux.splice(userIndex, 1);
-			return aux;
-		});
-	};
-
 	const handleOpenUserModal = () => {
 		setSelectedUserId(null);
 		setUserModalOpen(true);
@@ -141,6 +157,18 @@ const Users = () => {
 		setPageNumber(1);
 	};
 
+	const loadMore = () => {
+		setPageNumber(prevState => prevState + 1);
+	};
+
+	const handleScroll = e => {
+		if (!hasMore || loading) return;
+		const { scrollTop, scrollHeight, clientHeight } = e.currentTarget;
+		if (scrollHeight - (scrollTop + 100) < clientHeight) {
+			loadMore();
+		}
+	};
+
 	return (
 		<MainContainer>
 			<ConfirmationModal
@@ -182,7 +210,11 @@ const Users = () => {
 					</Button>
 				</MainHeaderButtonsWrapper>
 			</MainHeader>
-			<Paper className={classes.mainPaper} variant="outlined">
+			<Paper
+				className={classes.mainPaper}
+				variant="outlined"
+				onScroll={handleScroll}
+			>
 				<Table size="small">
 					<TableHead>
 						<TableRow>