Merge pull request #48 from art-institute-of-chicago/feature/paginate…

…-search-results

My Museum Tour search pagination

src/MyMuseumTourBuilder.jsx

@@ -63,7 +63,7 @@ const MyMuseumTourBuilder = (props) => {
               <div className="aic-ct__core">
                 <SearchBar {...SearchProps} />
                 <Themes {...SearchProps} />
-                <SearchResults />
+                <SearchResults {...SearchProps} />
               </div>
             </SearchProvider>
           </NavPage>

src/components/search/PageNumber.cy.jsx

@@ -0,0 +1,71 @@
+import React from "react";
+import SearchResults from "./SearchResults";
+import Pagination from "./Pagination";
+import item from "../../../cypress/fixtures/json/item.json";
+import { AppProvider } from "../../contexts/AppContext";
+import { SearchProvider } from "../../contexts/SearchContext";
+
+const pagination = { current_page: 1, total_pages: 2 };
+
+describe("<PageNumber />", () => {
+  it("Renders", () => {
+    cy.mount(
+      <AppProvider>
+        <SearchProvider
+          searchError={null}
+          searchFetching={false}
+          searchResultItems={[item]}
+          pagination={pagination}
+        >
+          <SearchResults />
+        </SearchProvider>
+      </AppProvider>,
+    );
+    cy.get(".m-paginator__page").should("have.length", pagination.total_pages);
+  });
+
+  it("Highlights the current page", () => {
+    cy.mount(
+      <AppProvider>
+        <SearchProvider
+          searchError={null}
+          searchFetching={false}
+          searchResultItems={[item]}
+          pagination={pagination}
+        >
+          <SearchResults />
+        </SearchProvider>
+      </AppProvider>,
+    );
+    cy.get(".s-active .m-paginator__page").should(
+      "have.text",
+      pagination.current_page,
+    );
+  });
+
+  it("Updates the page when another page is clicked", () => {
+    const goToPage = cy.stub().as("goToPage");
+    cy.mount(
+      <AppProvider>
+        <SearchProvider
+          searchError={null}
+          searchFetching={false}
+          searchResultItems={[item]}
+          pagination={pagination}
+        >
+          <Pagination goToPage={goToPage} />
+        </SearchProvider>
+      </AppProvider>,
+    );
+    const pageOne = cy.get(".m-paginator__page").first();
+    const pageTwo = cy.get(".m-paginator__page").last();
+    pageOne.click();
+    cy.get("@goToPage").should("not.be.called");
+    pageTwo
+      .click()
+      .invoke("text")
+      .then((page_number) => {
+        cy.get("@goToPage").should("be.calledOnceWith", parseInt(page_number));
+      });
+  });
+});

src/components/search/PageNumber.jsx

@@ -0,0 +1,26 @@
+import React from "react";
+import PropTypes from "prop-types";
+
+function PageNumber({ page, is_current_page, goToPage }) {
+  const handleClick = () => {
+    if (!is_current_page) {
+      goToPage(page);
+    }
+  };
+
+  return (
+    <li className={is_current_page ? "s-active" : ""}>
+      <a className="m-paginator__page f-buttons" onClick={handleClick}>
+        {page}
+      </a>
+    </li>
+  );
+}
+
+PageNumber.propTypes = {
+  page: PropTypes.number,
+  is_current_page: PropTypes.bool,
+  goToPage: PropTypes.func,
+};
+
+export default PageNumber;

src/components/search/Pagination.cy.jsx

@@ -0,0 +1,79 @@
+import React from "react";
+import SearchResults from "./SearchResults";
+import item from "../../../cypress/fixtures/json/item.json";
+import { AppProvider } from "../../contexts/AppContext";
+import { SearchProvider } from "../../contexts/SearchContext";
+
+const pagination = { current_page: 1, total_pages: 2 };
+
+describe("<Pagination />", () => {
+  it("Renders", () => {
+    cy.mount(
+      <AppProvider>
+        <SearchProvider
+          searchError={null}
+          searchFetching={false}
+          searchResultItems={[item]}
+          pagination={pagination}
+        >
+          <SearchResults />
+        </SearchProvider>
+      </AppProvider>,
+    );
+    cy.get(".m-paginator").should("exist");
+  });
+
+  it("Does not render with less than 2 pages", () => {
+    cy.mount(
+      <AppProvider>
+        <SearchProvider
+          searchError={null}
+          searchFetching={false}
+          searchResultItems={[item]}
+          pagination={{ current_page: 1, total_pages: 1 }}
+        >
+          <SearchResults />
+        </SearchProvider>
+      </AppProvider>,
+    );
+    cy.get(".m-paginator").should("not.exist");
+  });
+
+  it("Displays Previous and Next buttons", () => {
+    cy.mount(
+      <AppProvider>
+        <SearchProvider
+          searchError={null}
+          searchFetching={false}
+          searchResultItems={[item]}
+          pagination={pagination}
+        >
+          <SearchResults />
+        </SearchProvider>
+      </AppProvider>,
+    );
+    cy.get(".m-paginator__prev-next").should("exist");
+    cy.get(".m-paginator__prev-next li").should("have.length", 2);
+    cy.get(".m-paginator__prev").should("have.text", "Previous");
+    cy.get(".m-paginator__next").should("have.text", "Next");
+  });
+
+  it("Displays page buttons", () => {
+    cy.mount(
+      <AppProvider>
+        <SearchProvider
+          searchError={null}
+          searchFetching={false}
+          searchResultItems={[item]}
+          pagination={pagination}
+        >
+          <SearchResults />
+        </SearchProvider>
+      </AppProvider>,
+    );
+    cy.get(".m-paginator__pages li").should(
+      "have.length",
+      pagination.total_pages,
+    );
+  });
+});

src/components/search/Pagination.jsx

@@ -0,0 +1,197 @@
+import React, { useContext } from "react";
+import PropTypes from "prop-types";
+import { SearchContext } from "../../contexts/SearchContext";
+import PageNumber from "./PageNumber";
+import { range } from "./../../utils";
+
+/**
+ * Much of the code and several of the comments below have been adapted from the
+ * Illuminate/Pagination library in the Laravel framework.
+ */
+function Pagination({ goToPage }) {
+  const onEachSide = 3;
+  const perPage = 60;
+
+  const { pagination } = useContext(SearchContext);
+
+  const handleNextClick = () => {
+    if (hasMorePages()) {
+      goToPage(pagination.current_page + 1);
+    }
+  };
+
+  const handlePreviousClick = () => {
+    if (!onFirstPage()) {
+      goToPage(pagination.current_page - 1);
+    }
+  };
+
+  const hasPages = () => {
+    return pagination?.total_pages > 1;
+  };
+
+  const hasMorePages = () => {
+    return pagination.total_pages > pagination.current_page;
+  };
+
+  const onFirstPage = () => {
+    return pagination.current_page <= 1;
+  };
+
+  const smallSlider = () => {
+    return {
+      first: range(1, pagination.total_pages),
+      slider: null,
+      last: null,
+    };
+  };
+
+  const slider = () => {
+    let window = onEachSide + 4; // Is this 4 related to the 8 above?
+    if (!hasPages()) {
+      return { first: null, slider: null, last: null };
+    }
+    // If the current page is very close to the beginning of the page range, we will
+    // just render the beginning of the page range, followed by the last 2 of the
+    // links in this list, since we will not have room to create a full slider.
+    if (pagination.current_page <= window) {
+      return sliderTooCloseToBeginning(window);
+    }
+    // If the current page is close to the ending of the page range we will just get
+    // this first couple pages, followed by a larger window of these ending pages
+    // since we're too close to the end of the list to create a full on slider.
+    else if (pagination.current_page > pagination.total_pages - window) {
+      return sliderTooCloseToEnding(window);
+    }
+    // If we have enough room on both sides of the current page to build a slider we
+    // will surround it with both the beginning and ending caps, with this window
+    // of pages in the middle providing a Google style sliding paginator setup.
+    return fullSlider();
+  };
+
+  const sliderTooCloseToBeginning = (window) => {
+    let too_close_to_beginning = window + onEachSide;
+    return {
+      first: range(1, too_close_to_beginning),
+      slider: null,
+      last: getLast(),
+    };
+  };
+
+  const sliderTooCloseToEnding = (window) => {
+    let too_close_to_ending = window + (onEachSide - 1);
+    return {
+      first: getFirst(),
+      slider: null,
+      last: range(
+        pagination.total_pages - too_close_to_ending,
+        pagination.total_pages,
+      ),
+    };
+  };
+
+  const fullSlider = () => {
+    return {
+      first: getFirst(),
+      slider: getAdjacent(),
+      last: getLast(),
+    };
+  };
+
+  /**
+   * Get the page range for the current page window.
+   *
+   * @return {number[]}
+   */
+  const getAdjacent = () => {
+    return range(
+      pagination.current_page - onEachSide,
+      pagination.current_page + onEachSide,
+    );
+  };
+
+  /**
+   * Get the range of first pages of the slider
+   *
+   * @return {number[]}
+   */
+  const getFirst = () => {
+    return range(1, 2);
+  };
+
+  /**
+   * Get the range of last pages of the slider
+   *
+   * @return {number[]}
+   */
+  const getLast = () => {
+    return range(pagination.total_pages - 1, pagination.total_pages);
+  };
+
+  // I'm not sure what the 8 is meant to represent
+  let window =
+    pagination?.total_pages < onEachSide * 2 + 8 ? smallSlider() : slider();
+  let elements = [
+    window.first,
+    Array.isArray(window.slider) ? ["..."] : null,
+    window.slider,
+    Array.isArray(window.last) ? ["..."] : null,
+    window.last,
+  ].filter((element) => element); // Filter out nulls
+
+  return (
+    <>
+      {hasPages() && (
+        <nav className="m-paginator">
+          <ul className="m-paginator__prev-next">
+            <li>
+              <a
+                className="m-paginator__next f-buttons"
+                onClick={handleNextClick}
+              >
+                Next
+              </a>
+            </li>
+            <li>
+              <a
+                className="m-paginator__prev f-buttons"
+                onClick={handlePreviousClick}
+              >
+                Previous
+              </a>
+            </li>
+          </ul>
+          <ul className="m-paginator__pages">
+            {elements.map((element) =>
+              element.map((page, index) => (
+                <React.Fragment key={index}>
+                  {typeof page === "number" && page * perPage <= 10_000 && (
+                    <PageNumber
+                      page={page}
+                      is_current_page={page === pagination.current_page}
+                      goToPage={goToPage}
+                    />
+                  )}
+                  {typeof page === "string" && ( // Ellipses
+                    <li>
+                      <span className="f-buttons">&hellip;</span>
+                    </li>
+                  )}
+                </React.Fragment>
+              )),
+            )}
+          </ul>
+          <p className="m-paginator__current-page">
+            Page {pagination.current_page}
+          </p>
+        </nav>
+      )}
+    </>
+  );
+}
+
+Pagination.propTypes = {
+  goToPage: PropTypes.func,
+};
+
+export default Pagination;