feat: add pagination to home screen topic list

packages/concordia-app/src/components/Pagination/PaginatedTopicList/index.jsx

@@ -0,0 +1,63 @@
+import React, {
+  useEffect, useMemo, useState,
+} from 'react';
+import { useSelector } from 'react-redux';
+import _ from 'lodash';
+import { FORUM_CONTRACT } from 'concordia-shared/src/constants/contracts/ContractNames';
+import { drizzle } from '../../../redux/store';
+import TopicList from '../../TopicList';
+import PaginationComponent, { ITEMS_PER_PAGE } from '../index';
+import './styles.css';
+
+const {
+  contracts: {
+    [FORUM_CONTRACT]: {
+      methods: {
+        numTopics: { cacheCall: numTopicsChainData },
+      },
+    },
+  },
+} = drizzle;
+
+const PaginatedTopicList = () => {
+  const drizzleInitialized = useSelector((state) => state.drizzleStatus.initialized);
+  const drizzleInitializationFailed = useSelector((state) => state.drizzleStatus.failed);
+  const [pageNumber, setPageNumber] = useState(1);
+  const [numTopics, setNumTopics] = useState(null);
+  const [topicIds, setTopicIds] = useState([]);
+  const [numTopicsCallHash, setNumTopicsCallHash] = useState(null);
+
+  const numTopicsResult = useSelector((state) => state.contracts[FORUM_CONTRACT].numTopics[numTopicsCallHash]);
+
+  useEffect(() => {
+    if (drizzleInitialized && !drizzleInitializationFailed && numTopicsCallHash === null) {
+      setNumTopicsCallHash(numTopicsChainData());
+    }
+  }, [drizzleInitializationFailed, drizzleInitialized, numTopicsCallHash]);
+
+  useEffect(() => {
+    if (drizzleInitialized && !drizzleInitializationFailed && numTopics !== null) {
+      setTopicIds(_.rangeRight(Math.max(numTopics - ITEMS_PER_PAGE * pageNumber, 0),
+        numTopics - ITEMS_PER_PAGE * (pageNumber - 1)));
+    }
+  }, [pageNumber, drizzleInitializationFailed, drizzleInitialized, numTopics]);
+
+  useEffect(() => {
+    if (numTopicsResult) {
+      setNumTopics(numTopicsResult.value);
+    }
+  }, [numTopicsResult]);
+
+  const handlePageChange = (event, data) => {
+    setPageNumber(data.activePage);
+  };
+
+  return useMemo(() => (
+      <div id="paginated-topic-list">
+          <TopicList topicIds={topicIds} />
+          <PaginationComponent onPageChange={handlePageChange} numberOfItems={numTopics} />
+      </div>
+  ), [numTopics, topicIds]);
+};
+
+export default PaginatedTopicList;

packages/concordia-app/src/components/Pagination/PaginatedTopicList/styles.css

@@ -0,0 +1,4 @@
+#topic-list{
+    height: auto;
+    clear: both;
+}

packages/concordia-app/src/components/Pagination/index.jsx

@@ -0,0 +1,23 @@
+import React, { useMemo } from 'react';
+import { Icon, Pagination } from 'semantic-ui-react';
+
+export const ITEMS_PER_PAGE = 10;
+
+const PaginationComponent = (props) => {
+  const { numberOfItems, onPageChange } = props;
+  return useMemo(() => (
+      <Pagination
+        defaultActivePage={1}
+        ellipsisItem={{ content: <Icon name="ellipsis horizontal" />, icon: true }}
+        firstItem={{ content: <Icon name="angle double left" />, icon: true }}
+        lastItem={{ content: <Icon name="angle double right" />, icon: true }}
+        prevItem={{ content: <Icon name="angle left" />, icon: true }}
+        nextItem={{ content: <Icon name="angle right" />, icon: true }}
+        totalPages={Math.ceil(numberOfItems / ITEMS_PER_PAGE)}
+        disabled={numberOfItems <= ITEMS_PER_PAGE}
+        onPageChange={onPageChange}
+      />
+  ), [numberOfItems, onPageChange]);
+};
+
+export default PaginationComponent;

packages/concordia-app/src/components/TopicList/index.jsx

@@ -19,23 +19,15 @@ const TopicList = (props) => {
 
   useEffect(() => {
     if (drizzleInitialized && !drizzleInitializationFailed) {
-      const newTopicsFound = topicIds
+      setGetTopicCallHashes(
-        .filter((topicId) => !getTopicCallHashes
+        topicIds
-          .map((getTopicCallHash) => getTopicCallHash.id)
+          .map((topicId) => ({
-          .includes(topicId));
+            id: topicId,
-
+            hash: getTopicChainData(topicId),
-      if (newTopicsFound.length > 0) {
+          })),
-        setGetTopicCallHashes([
+      );
-          ...getTopicCallHashes,
-          ...newTopicsFound
-            .map((topicId) => ({
-              id: topicId,
-              hash: getTopicChainData(topicId),
-            })),
-        ]);
-      }
     }
-  }, [drizzleInitializationFailed, drizzleInitialized, getTopicCallHashes, topicIds]);
+  }, [drizzleInitializationFailed, drizzleInitialized, topicIds]);
 
   const topics = useMemo(() => topicIds
     .map((topicId) => {

packages/concordia-app/src/views/Home/Board/index.jsx

@@ -2,12 +2,9 @@ import React, { useMemo } from 'react';
 import { Button, Header } from 'semantic-ui-react';
 import { useSelector } from 'react-redux';
 import { useHistory } from 'react-router';
-import _ from 'lodash';
 import { useTranslation } from 'react-i18next';
 import PropTypes from 'prop-types';
-
+import PaginatedTopicList from '../../../components/Pagination/PaginatedTopicList';
-import TopicList from '../../../components/TopicList';
-
 import './styles.css';
 
 const Board = (props) => {
@@ -33,7 +30,8 @@ const Board = (props) => {
             : null}
           {/* eslint-disable-next-line no-nested-ternary */}
           {numberOfTopics > 0
-            ? (<TopicList topicIds={_.rangeRight(0, numberOfTopics)} />)
+          // eslint-disable-next-line react/jsx-no-undef
+            ? (<PaginatedTopicList />)
             : (!hasSignedUp
               ? (
                   <div id="no-topic-message" className="vertical-center-in-parent unselectable">

packages/concordia-contracts/.solhint.json

@@ -1,7 +1,7 @@
 {
   "extends": "solhint:recommended",
   "rules": {
-    "compiler-version": ["error","~0.8.0"],
+    "compiler-version": ["error","~0.8.1"],
     "func-visibility": ["warn",{"ignoreConstructors" : true}],
     "not-rely-on-time": "off",
     "state-visibility": "off"

packages/concordia-contracts/contracts/Forum.sol

@@ -1,5 +1,5 @@
 //SPDX-License-Identifier: MIT
-pragma solidity 0.8.0;
+pragma solidity 0.8.1;
 
 contract Forum {
     // Error messages for require()
@@ -17,6 +17,8 @@ contract Forum {
         bool signedUp;    // Helper variable for hasUserSignedUp()
     }
 
+    uint public numUsers;   // Total number of users
+
     mapping(address => User) users;
     mapping(string => address) usernameAddresses;
     address[] userAddresses;
@@ -30,6 +32,7 @@ contract Forum {
         users[msg.sender] = User(username, new uint[](0), new uint[](0), block.timestamp, true);
         usernameAddresses[username] = msg.sender;
         userAddresses.push(msg.sender);
+        numUsers++;
         emit UserSignedUp(username, msg.sender);
         return true;
     }

packages/concordia-contracts/contracts/Migrations.sol

@@ -1,5 +1,5 @@
 //SPDX-License-Identifier: MIT
-pragma solidity 0.8.0;
+pragma solidity 0.8.1;
 
 contract Migrations {
     address public owner;

packages/concordia-contracts/contracts/PostVoting.sol

@@ -1,5 +1,5 @@
 //SPDX-License-Identifier: MIT
-pragma solidity 0.8.0;
+pragma solidity 0.8.1;
 
 import "./Forum.sol";
 

packages/concordia-contracts/contracts/Voting.sol

@@ -1,5 +1,5 @@
 //SPDX-License-Identifier: MIT
-pragma solidity 0.8.0;
+pragma solidity 0.8.1;
 
 import "./Forum.sol";
 

packages/concordia-contracts/package.json

@@ -21,7 +21,7 @@
   "dependencies": {
     "@openzeppelin/contracts": "~3.3.0",
     "concordia-shared": "~0.1.0",
-    "truffle": "~5.1.58",
+    "truffle": "5.1.65",
     "unirest": "^0.6.0"
   },
   "devDependencies": {

packages/concordia-contracts/test/TestVoting.sol

@@ -1,5 +1,5 @@
 //SPDX-License-Identifier: MIT
-pragma solidity 0.8.0;
+pragma solidity 0.8.1;
 
 import "truffle/Assert.sol";
 import "truffle/DeployedAddresses.sol";

packages/concordia-contracts/truffle-config.js

@@ -7,7 +7,7 @@ module.exports = {
   // to customize your Truffle configuration!
   compilers: {
     solc: {
-      version: '0.8.0',
+      version: '0.8.1',
     },
   },
   contracts_build_directory: path.join(__dirname, 'build/'),