feat(pagination): add article pagination

 - add article pagination
 - Revise article like count prop validation from array to object
   since it has been modified in the back end

[starts #165273536]

src/components/ArticlePagination/ArticlePagination.scss

@@ -0,0 +1,6 @@
+.article-pagination {
+  display: flex;
+  flex-direction: row;
+  justify-content: space-around;
+  margin: 1rem;
+}

src/components/ArticlePagination/ArticlePagination.test.js

@@ -0,0 +1,49 @@
+import React from 'react';
+
+import { mount } from 'enzyme';
+
+import ArticlePagination from 'components/ArticlePagination';
+import Button from 'components/Button';
+
+describe('ArticlePagination', () => {
+  const props = {
+    previous: null,
+    next: 'next',
+    paginate: jest.fn(),
+    count: 20,
+  };
+  let wrapper = mount(<ArticlePagination {...props} />);
+
+  it('should render without crushing', () => {
+    expect(wrapper).toMatchSnapshot();
+  });
+
+  const previousButton = wrapper.find(Button).at(0);
+  const nextButton = wrapper.find(Button).at(1);
+
+  it('should disable buttons if null', () => {
+    expect(previousButton.props().disabled).toBe(true);
+    expect(nextButton.props().disabled).toBe(false);
+  });
+
+
+  it('should call the paginate function on button click', () => {
+    const event = {
+      target: {
+        type: 'button',
+        name: '',
+      },
+      preventDefault: jest.fn(),
+    };
+
+    nextButton.simulate('click', event);
+    expect(props.paginate).toBeCalled();
+    previousButton.simulate('click', event);
+
+
+    props.previous = 'previous';
+    wrapper = mount(<ArticlePagination {...props} />);
+    wrapper.find(Button).at(0).simulate('click', event);
+    expect(props.paginate).toBeCalled();
+  });
+});

src/components/ArticlePagination/__snapshots__/ArticlePagination.test.js.snap

@@ -0,0 +1,50 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`ArticlePagination should render without crushing 1`] = `
+<ArticlePagination
+  count={20}
+  next="next"
+  paginate={[MockFunction]}
+  previous={null}
+>
+  <div
+    className="article-pagination"
+  >
+    <Button
+      btnClass="fa fa-backward"
+      btnEvent={[Function]}
+      btnName=""
+      disabled={true}
+    >
+      <button
+        className="fa fa-backward"
+        disabled={true}
+        onClick={[Function]}
+        type="button"
+      />
+    </Button>
+    <span>
+      1
+       
+      /
+       
+      2
+       
+      pages 
+    </span>
+    <Button
+      btnClass="fa fa-forward"
+      btnEvent={[Function]}
+      btnName=""
+      disabled={false}
+    >
+      <button
+        className="fa fa-forward"
+        disabled={false}
+        onClick={[Function]}
+        type="button"
+      />
+    </Button>
+  </div>
+</ArticlePagination>
+`;

src/components/ArticlePagination/index.js

@@ -0,0 +1,65 @@
+// react
+import React from 'react';
+
+// Proptypes for validation
+import PropTypes from 'prop-types';
+
+// stylesheets
+import './ArticlePagination.scss';
+
+// Button component
+import Button from 'components/Button';
+
+const ArticlePagination = ({
+  previous, next, paginate, count, page
+}) => {
+  const pages = Math.ceil(count / 10);
+  return (
+
+    <div className="article-pagination">
+      <Button
+        btnName=""
+        btnClass="fa fa-backward"
+        btnEvent={(e) => {
+          e.preventDefault();
+          paginate(previous, -1);
+        }}
+        disabled={!previous}
+      />
+      <span>
+        {page || 1}
+        {' '}
+        {'/'}
+        {' '}
+        {pages}
+        {' '}
+        {'pages '}
+      </span>
+      <Button
+        btnName=""
+        btnClass="fa fa-forward"
+        btnEvent={(e) => {
+          e.preventDefault();
+          paginate(next, 1);
+        }}
+        disabled={!next}
+      />
+    </div>
+  );
+};
+
+ArticlePagination.defaultProps = {
+  next: null,
+  previous: null,
+};
+
+ArticlePagination.propTypes = {
+  next: PropTypes.string,
+  page: PropTypes.number.isRequired,
+  count: PropTypes.number.isRequired,
+  previous: PropTypes.string,
+  paginate: PropTypes.func.isRequired,
+};
+
+
+export default ArticlePagination;

src/components/Button/index.js

@@ -7,7 +7,7 @@ import PropTypes from 'prop-types';
 const Button = (props) => {
   // Destructure props
   const {
-    btnClass, btnName, btnEvent,
+    btnClass, btnName, btnEvent, disabled
   } = props;
 
   return (
@@ -16,14 +16,21 @@ const Button = (props) => {
       className={btnClass}
       type="button"
       onClick={btnEvent}
+      disabled={disabled}
     >
       {btnName}
     </button>
   );
 };
 
+// Default proptypes
+Button.defaultProps = {
+  disabled: false,
+};
+
 // Props validation
 Button.propTypes = {
+  disabled: PropTypes.bool,
   btnName: PropTypes.string.isRequired,
   btnClass: PropTypes.string.isRequired,
   btnEvent: PropTypes.func.isRequired,

src/components/Login/__snapshots__/login.test.js.snap

@@ -47,6 +47,7 @@ exports[`login component matches the snapshot 1`] = `
           btnClass="login__button"
           btnEvent={[Function]}
           btnName="Login"
+          disabled={false}
         />
         <i
           className="login__forgot__pwd"
@@ -129,6 +130,7 @@ exports[`login component should render without crsshing 1`] = `
           btnClass="login__button"
           btnEvent={[Function]}
           btnName="Login"
+          disabled={false}
         />
         <i
           className="login__forgot__pwd"

src/components/SignupForm/__snapshots__/SignupForm.test.js.snap

@@ -100,6 +100,7 @@ exports[`SignupForm Component matches the snapshot 1`] = `
         btnClass="signupForm__button"
         btnEvent={[Function]}
         btnName="Sign up"
+        disabled={false}
         id="signupForm__button"
       />
     </form>

src/pages/Landing/Landing.test.js

@@ -40,4 +40,19 @@ describe('Article Column', () => {
     const component = shallow(<ArticleColumn columnTitle="Most Recent" articles={[mockArticle()]} />);
     expect(component.exists()).toBe(true);
   });
+
+  it('should call the get articles  function', () => {
+    const getArticlesFn = jest.fn();
+    const props = {
+      next: 'nexturl',
+      previous: 'previousurl',
+      count: 10,
+      articles: [],
+      getArticles: getArticlesFn,
+
+    };
+    const wrapper = shallow(<LandingPage {...props} />);
+    wrapper.instance().paginate();
+    expect(getArticlesFn).toBeCalled();
+  });
 });

src/pages/Landing/index.js

@@ -3,7 +3,6 @@ import React, { Component } from 'react';
 
 // third-party libraries
 import { ToastContainer } from 'react-toastify';
-import { bindActionCreators } from 'redux';
 import { connect } from 'react-redux';
 import PropTypes from 'prop-types';
 
@@ -15,19 +14,44 @@ import Navbar from 'components/NavBar';
 import Footer from 'components/Footer';
 import Loader from 'components/Loader';
 import { getAllArticles } from 'store/actions/articleActions';
+import ArticlePagination from 'components/ArticlePagination';
 import ArticleColumn from './ArticleColumn';
 
 
 export class LandingPage extends Component {
+  constructor(props) {
+    super(props);
+    this.state = {
+      page: 1,
+    };
+  }
+
   componentDidMount() {
     const { getArticles } = this.props;
 
     // fetch articles
     getArticles();
   }
 
+
+  paginate = (apiCallUrl, Increment) => {
+    const { getArticles } = this.props;
+    const { page } = this.state;
+    this.setState({
+      page: page + Increment
+    });
+
+    getArticles(apiCallUrl);
+  };
+
+
   render() {
-    const { articles, isFetching } = this.props;
+    const {
+      articles, isFetching, previous, count, next
+    } = this.props;
+    const { page } = this.state;
+
+
     return (
 
       // Navbar
@@ -65,7 +89,18 @@ export class LandingPage extends Component {
             <ArticleColumn columnTitle="Most Popular" articles={articles} />
             <ArticleColumn columnTitle="Most Liked" articles={articles} />
             <ArticleColumn columnTitle="Most Recent" articles={articles} />
+
           </div>
+          <div>
+            <ArticlePagination
+              paginate={this.paginate}
+              next={next}
+              previous={previous}
+              count={count}
+              page={page}
+            />
+          </div>
+
           <Footer />
         </div>
       </div>
@@ -75,6 +110,9 @@ export class LandingPage extends Component {
 
 // proptype validation
 LandingPage.propTypes = {
+  next: PropTypes.string,
+  count: PropTypes.number,
+  previous: PropTypes.string,
   getArticles: PropTypes.func,
   isFetching: PropTypes.bool,
   articles: PropTypes.arrayOf(PropTypes.shape({
@@ -105,6 +143,9 @@ LandingPage.propTypes = {
 
 LandingPage.defaultProps = {
   articles: [],
+  next: null,
+  previous: null,
+  count: 0,
   isFetching: false,
   getArticles: () => { },
 };
@@ -115,15 +156,25 @@ LandingPage.defaultProps = {
  * @return {articles} - An aray of articles
  *
  */
-const mapStateToProps = state => state.articles;
+// const mapStateToProps = state => state.articles;
+const mapStateToProps = (state) => {
+  const {
+    next, count, previous, articles
+  } = state.articles;
+  return {
+    next, count, previous, articles
+  };
+};
+
 /**
  * This is a function to pass the state as a prop.
  * @param {dispatch}  - The dispatch function
  * @return {getArticles} - The thunk to fetch articles
  *
  */
-const mapDispatchToProps = dispatch => bindActionCreators({
-  getArticles: () => getAllArticles(),
-}, dispatch);
+
+const mapDispatchToProps = dispatch => ({
+  getArticles(apiCallUrl) { dispatch(getAllArticles(apiCallUrl)); },
+});
 
 export default connect(mapStateToProps, mapDispatchToProps)(LandingPage);