MultiDropdownList

Image to be displayed

MultiDropdownList creates a dropdown based multiple selection list UI component that is connected to a database field. It is used for filtering results based on the current selection from a list of items.

Note

This component is exactly like the MultiList component except the UI is based on a dropdown, ideal for showing additional UI filters while conserving screen space.

Example uses:

  • create an e-commerce facet like search experience.
  • create a filter for airlines to fly by in a flight booking experience.

Usage

Basic Usage

<MultiDropdownList
  componentId="CitySensor"
  dataField="group.group_city.raw"
  title="Cities"
/>

Usage With All Props

<MultiDropdownList
  componentId="CitySensor"
  dataField="group.group_city.raw"
  title="Cities"
  size={100}
  sortBy="count"
  defaultValue={["London"]}
  showCount={true}
  placeholder="Search City"
  react={{
    and: ["CategoryFilter", "SearchFilter"]
  }}
  showFilter={true}
  filterLabel="City"
  URLParams={false}
  loader="Loading ..."
/>

Props

  • componentId String unique identifier of the component, can be referenced in other components’ react prop.

  • dataField String DB data field to be mapped with the component’s UI view. The dropdown list items are filtered by a database query on this field. This field is used for doing an aggregation and returns the result. We’re using a .raw multifield here. You can use a field of type keyword or not_analyzed depending on your Elasticsearch cluster.

  • nestedField String [optional] use to set the nested mapping field that allows arrays of objects to be indexed in a way that they can be queried independently of each other. Applicable only when dataField is a part of nested type.

  • loader String or JSX [optional] to display an optional loader while fetching the options.

  • title String or JSX [optional] title of the component to be shown in the UI.

  • size Number [optional] control how many items to display in the List. Defaults to 100.

  • sortBy String [optional] property that decides on how to sort the list items, accepts one of count, asc or desc as valid values.

    • count sorts the list based on the count occurences, with highest value at the top.
    • asc sorts the list in the ascending order of the list item (Alphabetical).
    • desc sorts the list in the descending order of the term. Defaults to count.
  • defaultValue String Array [optional] select one or more options from the dropdown list on mount. Accepts an Array object containing the items that should be selected.

  • value String Array [optional] controls the current value of the component. It selects the item from the list (on mount and on update). Use this prop in conjunction with onChange function.

  • queryFormat String [optional] queries the selected items from the list in one of two modes: or, and.

    • Defaults to or which queries for results where any of the selected list items are present.
    • In and mode, the applied query filters results where all of the selected items are present.
  • showCount Boolean [optional] show count of number of occurences besides an item. Defaults to true.

  • showSearch Boolean [optional] whether to show a searchbox to filter the list items locally. Defaults to false.

  • transformData Function [optional] allows transforming the data to render inside the list. You can change the order, remove, or add items, tranform their values with this method. It provides the data as param which is an array of objects of shape { key: <string>, doc_count: <number> } and expects you to return the array of objects of same shape.

  • showMissing Boolean [optional] defaults to false. When set to true it also retrives the aggregations for missing fields under the label specified by missingLabel.

  • missingLabel String [optional] defaults to N/A. Specify a custom label to show when showMissing is set to true.

  • placeholder String [optional] placeholder to be displayed in the dropdown searchbox.

  • showFilter Boolean [optional] show as filter when a value is selected in a global selected filters view. Defaults to true.

  • filterLabel String [optional] An optional label to display for the component in the global selected filters view. This is only applicable if showFilter is enabled. Default value used here is componentId.

  • URLParams Boolean [optional] enable creating a URL query string parameter based on the selected value of the list. This is useful for sharing URLs with the component state. Defaults to false.

  • showLoadMore Boolean [optional] defaults to false and works only with elasticsearch >= 6 since it uses composite aggregations. This adds a “Load More” button to load the aggs on demand combined with the size prop. Composite aggregations are in beta and this is an experimental API which might change in a future release.

    Note: Composite aggregations do not support sorting by count. Hence with showLoadMore, you can only sort by: asc or desc order. sortBy prop defaults to asc when showLoadMore prop is used.

  • renderItem Function [optional] customize the rendered list via a function which receives the item label, count & isSelected and expects a JSX or String back. For example:

    renderItem={(label, count, isSelected) => (
        <div>
            {label}
            <span style={{
                marginLeft: 5, color: isSelected ? 'red' : 'dodgerblue'
            }}>
                {count}
            </span>
        </div>
    )}
  • render Function [optional] an alternative callback function to renderItem, where user can define how to render the view based on all the data changes.
    It accepts an object with these properties:

    • loading: boolean indicates that the query is still in progress
    • error: object An object containing the error info
    • data: array An array of results obtained from the applied query.
    • value: array current selected values.
    • handleChange: function A callback function can be used to mark the list value as selected.
    • downshiftProps: object provides all the control props from downshift which can be used to bind list items with click/mouse events. Read more about it here.

      <MultiDropdownList
      render={({
          loading,
          error,
          data,
          handleChange,
      }) => {
          if(loading) {
              return <div>Fetching Results.</div>
          }
          if(error) {
              return (
                  <div>
                      Something went wrong! Error details {JSON.stringify(error)}
                  </div>
              )
          }
          return data.map(item => (
              <div onClick={() => handleChange(item.key)} key={item.key}>
                  <span>{item.key}</span>
                  <span>{item.doc_count}</span>
              </div>
          ))
      }}
      />

      Or you can also use render function as children

      <MultiDropdownList>
      {
          ({
              loading,
              error,
              data,
              value,
              handleChange,
              downshiftProps
          }) => (
              // return UI to be rendered
          )
      }
      </MultiDropdownList>
  • renderError String or JSX or Function [optional] can be used to render an error message in case of any error.

    renderError={(error) => (
            <div>
                Something went wrong!<br/>Error details<br/>{error}
            </div>
        )
    }
  • renderNoResults Function [optional] can be used to render a message in case of no list items.

    renderNoResults={() => <p>No Results Found!</p>}
  • onChange function [optional] is a callback function which accepts component’s current value as a parameter. It is called when you are using the value prop and the component’s value changes. This prop is used to implement the controlled component behavior.

  • onError Function [optional] gets triggered in case of an error and provides the error object, which can be used for debugging or giving feedback to the user if needed.

    Demo


Styles

MultiDropdownList component supports innerClass prop with the following keys:

  • title
  • select
  • list
  • icon
  • count

Read more about it here.

Extending

MultiDropdownList component can be extended to

  1. customize the look and feel with className, style,
  2. update the underlying DB query with customQuery, defaultQuery,
  3. connect with external interfaces using beforeValueChange, onValueChange and onQueryChange,
  4. specify how options should be filtered or updated using react prop.
<MultiDropdownList
  ...
  className="custom-class"
  style={{"paddingBottom": "10px"}}
  customQuery={
    function(value, props) {
      return {
        query: {
            match: {
                data_field: "this is a test"
            }
        }
      }
    }
  }
  defaultQuery={
    function(value, props) {
      return {
          timeout: '1s'
      }
    }
  }
  beforeValueChange={
    function(value) {
      // called before the value is set
      // returns a promise
      return new Promise((resolve, reject) => {
        // update state or component props
        resolve()
        // or reject()
      })
    }
  }
  onValueChange={
    function(value) {
      console.log("current value: ", value)
      // set the state
      // use the value with other js code
    }
  }
  onQueryChange={
    function(prevQuery, nextQuery) {
      // use the query with other js code
      console.log('prevQuery', prevQuery);
      console.log('nextQuery', nextQuery);
    }
  }
  // specify how and which options are filtered using `react` prop.
  react={
    "and": ["pricingFilter", "dateFilter"],
    "or": ["searchFilter"]
  }
/>
  • className String CSS class to be injected on the component container.
  • style Object CSS styles to be applied to the MultiDropdownList component.
  • customQuery Function takes value and props as parameters and returns the data query to be applied to the component, as defined in Elasticsearch Query DSL. Note: customQuery is called on value changes in the MultiDropdownList component as long as the component is a part of react dependency of at least one other component.
  • defaultQuery Function takes value and props as parameters and returns the data query to be applied to the source component, as defined in Elasticsearch Query DSL, which doesn’t get leaked to other components. Read more about it here.
  • beforeValueChange Function is a callback function which accepts component’s future value as a parameter and returns a promise. It is called everytime before a component’s value changes. The promise, if and when resolved, triggers the execution of the component’s query and if rejected, kills the query execution. This method can act as a gatekeeper for query execution, since it only executes the query after the provided promise has been resolved.
  • onValueChange Function is a callback function which accepts component’s current value as a parameter. It is called everytime the component’s value changes. This prop is handy in cases where you want to generate a side-effect on value selection. For example: You want to show a pop-up modal with the valid discount coupon code when list item(s) is/are selected in a “Discounted Price” MultiDropdownList.
  • onQueryChange Function is a callback function which accepts component’s prevQuery and nextQuery as parameters. It is called everytime the component’s query changes. This prop is handy in cases where you want to generate a side-effect whenever the component’s query would change.
  • react Object specify dependent components to reactively update MultiDropdownList’s options.

    • key String one of and, or, not defines the combining clause.

      • and clause implies that the results will be filtered by matches from all of the associated component states.
      • or clause implies that the results will be filtered by matches from at least one of the associated component states.
      • not clause implies that the results will be filtered by an inverse match of the associated component states.
    • value String or Array or Object

      • String is used for specifying a single component by its componentId.
      • Array is used for specifying multiple components by their componentId.
      • Object is used for nesting other key clauses.

Examples

MultiDropdownList with default props