Filter recent earthquakes

Build a user interface (UI) with Calcite Design System. This tutorial will provide an overview of Calcite Components, which can be replicated and scaled to solve complex problems. You will:

Learn how to execute a query to access attributes from a feature service.
Add a calcite-notice to dynamically populate the number of records found in the query.
Dynamically add calcite-card's to display individual records from the query.
- Create a calcite-button that links to a record's location in Map Viewer.

This tutorial leverages vanilla JavaScript, but these concepts and methods of interaction are applicable across frameworks. For a tutorial that includes a map, visit Create a mapping app.

Prerequisites

ArcGIS developer account

You need a free ArcGIS developer account or an account associated with an ArcGIS Online organization to access the services used in this tutorial.

Steps

Create a new pen

Go to CodePen to create a new pen for your application.

Construct the HTML

In CodePen > HTML, add HTML to create a page with a <body> tag. Also, add a <main> section.

The <!DOCTYPE html> tag is not required in CodePen. If you are using a different editor or running the page on a local server, be sure to add this tag to the top of your HTML page.

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<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <title>Calcite Components: Filter recent earthquakes</title>
  </head>
  <style>
  </style>
  <body>
    <main>
    </main>
  </body>
  <script>
  </script>
</html>

To access Calcite Design System web components, add references to Calcite Components in the <head> element.

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<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
  <title>Calcite Components: Filter recent earthquakes</title>

  <script src="https://js.arcgis.com/calcite-components/2.13.2/calcite.esm.js" type="module"></script>
  <link rel="stylesheet" href="https://js.arcgis.com/calcite-components/2.13.2/calcite.css" />

</head>
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Next, you will organize the contents of the application. In the main section, add a calcite-shell and calcite-panel with attributes of heading and heading-level to contain the earthquake results.

The heading and heading-level attributes arrange page hierarchy throughout your application to support a larger audience. Since this is the first header on the page, set the heading-level value to "1".

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    <calcite-shell>
      <!-- Panel to display records -->
      <calcite-panel heading="Earthquake results" heading-level="1" description="Search by location to display results">

      </calcite-panel>
    </calcite-shell>
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Showcase the records

You will continue building HTML content, which the user will have the ability to adjust. The content will change as the user interacts with the application.

In the calcite-panel, add a calcite-filter, which will be used to query the earthquakes feature service.

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        <!-- Filter records -->
        <calcite-filter placeholder="Try searching Alaska"></calcite-filter>
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Next, add two calcite-notice elements, each accompanied with an unique id attribute. The first will provide guidance on the app's initial state and be set as open. The second will supply on-demand feedback to the user.

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    <calcite-shell>
      <!-- Panel to display records -->
      <calcite-panel heading="Earthquake results" heading-level="1" description="Search by location to display results">

        <!-- Filter records -->
        <calcite-filter placeholder="Try searching Alaska"></calcite-filter>

        <!-- Provide details of the app's initial state -->
        <calcite-notice id="initial-note" open icon="information">
          <div slot="title">Try searching a place of interest</div>
          <div slot="message">Results will display when text is entered.</div>
          </div>
        </calcite-notice>

        <!-- An open property will be added to display the number of filtered records -->
        <calcite-notice id="note">

        </calcite-notice>

      </calcite-panel>
    </calcite-shell>
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In the second calcite-notice, add a div and place it in the title slot, which will be used later to populate the number of earthquake results using the id attribute.

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        <!-- An open property will be added to display the number of filtered records -->
        <calcite-notice id="note">

          <div id="number-records" slot="title">
            <!-- Content is automatically generated -->
          </div>

        </calcite-notice>
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Next, add a div with a class attribute to hold the earthquake results. Also, place calcite-pagination in the panel's footer slot, and add a page-size attribute to specify the number of items to display per page.

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        <!-- Container with Cards -->
        <div class="card-container">
          <!-- Content is automatically generated -->
        </div>
        <!-- Pagination -->
        <calcite-pagination slot="footer" page-size="12" style="visibility:hidden"></calcite-pagination>
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Query the data

You will add JavaScript functionality to query an earthquakes feature service via a search term entered by a user.

First, create constant variables referencing the calcite-filter, calcite-pagination, both calcite-notice's, and the card-container CSS class to reference the elements later on.

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  const filterElement = document.querySelector("calcite-filter");
  const paginationElement = document.querySelector("calcite-pagination");
  const initialNoticeElement = document.getElementById("initial-note");
  const noticeElement = document.getElementById("note");
  const cardContainer = document.querySelector(".card-container");
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Next, query the earthquakes service using the Fetch API. When successful, parse the response with Response.json(), and the map() method to capture the features.

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  /* Fetch the earthquakes feature service */
  fetch("https://services9.arcgis.com/RHVPKKiFTONKtxq3/ArcGIS/rest/services/USGS_Seismic_Data_v1/FeatureServer/0/query?where=1%3D1&outFields=*&f=json")
    .then((response) => response.json())
    .then(({ features }) => features.map(({ attributes }) => attributes))

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Filter the results

Next, with the response parsed, you will filter and display the user-defined results.

Filter results using a named function expression, initFilter. Set the calcite-filter component's items property using the constant variable defined in the step above.

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  /* Fetch the earthquakes feature service */
  fetch("https://services9.arcgis.com/RHVPKKiFTONKtxq3/ArcGIS/rest/services/USGS_Seismic_Data_v1/FeatureServer/0/query?where=1%3D1&outFields=*&f=json")
    .then((response) => response.json())
    .then(({ features }) => features.map(({ attributes }) => attributes))

    .then((attributes) => initFilter(attributes));

  /* Filter the results to display */
  const initFilter = (items) => {
    filterElement.items = items;

  };

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In initFilter, add a listener for the calciteFilterChange event to watch for changes to the filter's value. Then, go back to the first page by changing pagination's startItem and totalItems properties. Lastly, create a conditional to add cards when the filter's value is not falsey.

The filter's filteredItems property contains all of the items when there is no value. To create search functionality, you need to only add cards when the user has entered a query term.

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  /* Filter the results to display */
  const initFilter = (items) => {
    filterElement.items = items;

    document.addEventListener("calciteFilterChange", () => {
      paginationElement.startItem = 1;
      paginationElement.totalItems = 0;

      // When a Filter value is present
      // Create Cards, update Pagination, and number of responses
      if (filterElement.value) {

        // If additional pages are populated, display Pagination
        if (paginationElement.totalItems > paginationElement.pageSize) {
          paginationElement.style.visibility = "visible";
        }

    });

  };
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When there is no text present in the calcite-filter, set the initial notice's open property to true.

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  /* Filter the results to display */
  const initFilter = (items) => {
    filterElement.items = items;

    document.addEventListener("calciteFilterChange", () => {
      paginationElement.startItem = 1;
      paginationElement.totalItems = 0;

      paginationElement.style.visibility = "hidden";

      // When a Filter value is present
      // Create Cards, update Pagination, and number of responses
      if (filterElement.value) {

        // If additional pages are populated, display Pagination
        if (paginationElement.totalItems > paginationElement.pageSize) {
          paginationElement.style.visibility = "visible";
        }

      } else {
        // If no text is present in the Filter, display the initial notice
        initialNoticeElement.open = true;
      }

    });

  };
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Next, within calciteFilterChange, you will display the pagination component when the totalItems filtered earthquakes is greater than the specified pageSize value. Set the calcite-pagination component's visibility CSS property to "hidden". When there is more than one page of results, you will change the CSS property's value to "visible".

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  /* Filter the results to display */
  const initFilter = (items) => {
    filterElement.items = items;

    document.addEventListener("calciteFilterChange", () => {
      paginationElement.startItem = 1;
      paginationElement.totalItems = 0;

      paginationElement.style.visibility = "hidden";

      // When a Filter value is present
      // Create Cards, update Pagination, and number of responses
      if (filterElement.value) {

        // If additional pages are populated, display Pagination
        if (paginationElement.totalItems > paginationElement.pageSize) {
          paginationElement.style.visibility = "visible";
        }

      } else {
        // If no text is present in the Filter, display the initial notice
        initialNoticeElement.open = true;
      }

    });

  };
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Display the earthquakes

To display the earthquakes you will store each result's attributes in a calcite-card. You will also add a calcite-button, which, when accessed, will open the earthquake location in Map Viewer.

Place the filtered earthquake(s) into calcite-card component(s) residing in the card-container class with a named function expression, createCard.

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  /* Create Cards and their content */
  const createCard = (item) => {
    const headingName = item.place.replace(/[;']/g, "");
    // Populate Card content
    if (cardContainer.childElementCount < paginationElement.pageSize) {
      const cardString =
        `<calcite-card id="card-${item.OBJECTID}">
        <span slot="heading">
          <b>${item.place}</b>
        </span>
        <span slot="description">
          Occurred on: ${new Date(item.eventTime)}
        </span>
        <calcite-chip
          appearance="outline"
          scale="s"
          icon="graph-time-series"
        >
          Magnitude: ${item.mag}
        </calcite-chip>
        <calcite-button
          label="Open ${headingName} in map"
          icon-end="launch"
          slot="footer-end"
          target="_blank"
          width="full"
          href="https://www.arcgis.com/apps/mapviewer/index.html?` +
        `marker=${item.longitude};${item.latitude};` + // Marker (lng, lat)
        `4326;` + // Coordinate system
        headingName + `;` +
        `;` + // Marker image
        `Magnitude: ${item.mag}&` +
        `center=${item.longitude};${item.latitude}&` +
        `level=6"
        >
          Open in map
        </calcite-button>
        </calcite-card>`;
      const cardElement = document
        .createRange()
        .createContextualFragment(cardString);
      cardContainer.appendChild(cardElement);
    }
  };
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To create the cards, call createCard in the calciteFilterChange event listener for each feature that matches the filter value. Also, clear the cardContainer content, which contains previous filter results.

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  /* Filter the results to display */
  const initFilter = (items) => {
    filterElement.items = items;

    document.addEventListener("calciteFilterChange", () => {
      paginationElement.startItem = 1;
      paginationElement.totalItems = 0;

      paginationElement.style.visibility = "hidden";

      cardContainer.innerHTML = "";

      // When a Filter value is present
      // Create Cards, update Pagination, and number of responses
      if (filterElement.value) {

        filterElement.filteredItems.forEach((item) => createCard(item));
        paginationElement.totalItems = filterElement.filteredItems.length;

        // If additional pages are populated, display Pagination
        if (paginationElement.totalItems > paginationElement.pageSize) {
          paginationElement.style.visibility = "visible";
        }

      } else {
        // If no text is present in the Filter, display the initial notice
        initialNoticeElement.open = true;
      }

    });

  };
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Next, you will display the number of earthquake results for the user. Create a function, showNumberOfResponses and post the number of responses to the calcite-notice title. To ensure content is accessible to users, remove the initial notice's open attribute and set the results notice open property to true.
- The innerHTML, kind, and icon attributes will change depending on the number of responses.

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  /* Display the number of responses in a Notice */
  function showNumberOfResponses(responseNumber) {
    const note = document.getElementById("note");
    const numberRecordsNote = document.getElementById("number-records");
    // If 0 responses, add "Sorry" to the Notice text
    // Add the Notice color and icon
    if (responseNumber === 0) {
      responseNumber = `Sorry, ${responseNumber}`
      note.kind = "danger";
      note.icon = "exclamation-mark-triangle";
    } else {
      note.kind = "brand";
      note.icon = "information";
    }
    // Hide the initial notice
    initialNoticeElement.removeAttribute("open");
    // Notice text
    numberRecordsNote.innerHTML = `${responseNumber} records found.`;
    noticeElement.open = true;
  }
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Similar to creating the cards, add the showNumberOfResponses function call to the calciteFilterChange event listener's callback function. When no text is present in the calcite-filter, set the filtered notice's open attribute to false, and the calcite-pagination's visibility to "hidden".

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  /* Filter the results to display */
  const initFilter = (items) => {
    filterElement.items = items;

    document.addEventListener("calciteFilterChange", () => {
      paginationElement.startItem = 1;
      paginationElement.totalItems = 0;

      // Prevent display if no Filter value is present
      noticeElement.open = false;

      paginationElement.style.visibility = "hidden";

      cardContainer.innerHTML = "";

      // When a Filter value is present
      // Create Cards, update Pagination, and number of responses
      if (filterElement.value) {

        filterElement.filteredItems.forEach((item) => createCard(item));
        paginationElement.totalItems = filterElement.filteredItems.length;

        showNumberOfResponses(filterElement.filteredItems.length);

        // If additional pages are populated, display Pagination
        if (paginationElement.totalItems > paginationElement.pageSize) {
          paginationElement.style.visibility = "visible";
        }

      } else {
        // If no text is present in the Filter, display the initial notice
        initialNoticeElement.open = true;
      }

    });

  };
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Add a listener for pagination's calcitePaginationChange event so users can view subsequent filtered items when changing pages. Display a subset of the filteredItems, starting at the pagination's startItem property, and ending at the sum of the startItem and pageSize properties.

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  /* Update Cards when interacting with Pagination */
  document.addEventListener("calcitePaginationChange", ({ target }) => {

    const displayItems = filterElement.filteredItems.slice(
      target.startItem - 1,
      target.startItem - 1 + target.pageSize
    );

  });
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Lastly, you will update the cards when interacting with calcite-pagination. Clear the cardContainer contents with any previous filtered results, and call createCard in the calcitePaginationChange event listener.

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  /* Update Cards when interacting with Pagination */
  document.addEventListener("calcitePaginationChange", ({ target }) => {

    cardContainer.innerHTML = "";

    const displayItems = filterElement.filteredItems.slice(
      target.startItem - 1,
      target.startItem - 1 + target.pageSize
    );

    displayItems.forEach((item) => createCard(item));

  });
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Add styling

The application's functionality is now complete. Make final design tweaks to the interface using CSS styling.

Add styling to the card-container class using CSS grid layout, calcite-chip's color to display the earthquake magnitude, and calcite-notice positioning.

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<style>

  .card-container {
    margin: 0.75rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    grid-gap: 1rem;
    justify-content: space-evenly;
  }

  calcite-chip {
    --calcite-chip-border-color: var(--calcite-color-status-danger);
    --calcite-chip-text-color: var(--calcite-color-status-danger);
  }

  calcite-notice {
    position: relative;
    margin: 0.75rem;
  }


</style>
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Run the application

In CodePen, run your code to display the application.