
SingleDropdownList creates a dropdown list based single select UI component. It is used for filtering results based on the current selection from a list of items.
Note
This component is exactly like the SingleList component except the UI is based on a dropdown, ideal for showing additional UI filters while conserving screen space.
Example uses:
- select a category from a list of categories for filtering e-commerce search results.
- filtering restaurants by a cuisine choice.
Usage
Basic Usage
<SingleDropdownList componentId="CitySensor" dataField="group.group_city.raw" title="Cities" />Usage With All Props
<SingleDropdownList
	componentId="CitySensor"
	dataField="group.group_city.raw"
	title="Cities"
	size={100}
	sortBy="count"
	defaultValue="London"
	showCount={true}
	placeholder="Search City"
	selectAllLabel="All Cities"
	react={{
		and: ['CategoryFilter', 'SearchFilter'],
	}}
	showFilter={true}
	filterLabel="City"
	URLParams={false}
	loader="Loading ..."
    endpoint={{
      url:"https://appbase-demo-ansible-abxiydt-arc.searchbase.io/recipes-demo/_reactivesearch.v3", //mandatory
      headers:{
        // relevant headers
      },
      method: 'POST'
    }}       
/>Props
- 
componentId Stringunique identifier of the component, can be referenced in other components'reactprop.
- 
endpoint Object[optional] endpoint prop provides the ability to query a user-defined backend service for this component, overriding the data endpoint configured in the ReactiveBase component. Works only whenenableAppbaseistrue. Accepts the following properties:- url String[Required] URL where the data cluster is hosted.
- headers Object[optional]
 set custom headers to be sent with each server request as key/value pairs.
- method String[optional]
 set method of the API request.
- body Object[optional]
 request body of the API request. When body isn't set and method is POST, the request body is set based on the component's configured props.
 - Overrides the endpoint property defined in ReactiveBase.
- If required, use transformResponseprop to transform response in component-consumable format.
 
- url 
- 
dataField Stringdata field to be connected to the component's UI view. This field is used for doing an aggregation and returns the result. We're using a.rawmultifield here. You can use a field of typekeywordornot_analyzeddepending on your Elasticsearch cluster.
- 
nestedField String[optional] use to set thenestedmapping 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 ofnestedtype.
- 
title String or JSX[optional] title of the component to be shown in the UI.
- 
loader String or JSX[optional] to display an optional loader while fetching the options.
- 
size Number[optional] number of list items to be displayed.Note: - Appbase users should use the aggregationSizeprop instead. Thesizeprop would only set the size forhitsnot theaggregations.
- We recommend Appbase users to not use the sizeprop unless they are usinghitsbecause it can impact the query performance.
 
- Appbase users should use the 
- 
aggregationSize To set the number of buckets to be returned by aggregations. Note: This prop is only applicable when enableAppbaseis set totrue.
- 
sortBy String[optional] property that decides on how to sort the list items, accepts one ofcount,ascordescas valid values.countsorts the list based on the count occurences, with highest value at the top.ascsorts the list in the ascending order of the list item (Alphabetical).descsorts the list in the descending order of the term. Defaults tocount.
- 
defaultValue string[optional] selects intial option from the dropdown list on mount.
- 
value string[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 withonChangefunction.
- 
showCount Boolean[optional] show count of number of occurences besides an item. Defaults totrue.
- 
showSearch Boolean[optional] whether to show a searchbox to filter the list items locally. Defaults tofalse.
- 
showClear Boolean[optional] whether to show a clear button to clear the entered text in the searchbox. Defaults tofalse.
- 
showMissing Boolean[optional] defaults tofalse. When set totrueit also retrives the aggregations for missing fields under the label specified bymissingLabel.
- 
missingLabel String[optional] defaults toN/A. Specify a custom label to show whenshowMissingis set totrue.
- 
placeholder String[optional] placeholder to be displayed in the select box. It'll be only applicable when no value is selected.
- 
searchPlaceholder String[optional] placeholder to be displayed in the search box. Defaults toType here to search....
- 
selectAllLabel String[optional] if provided, shows an extra option to select all the options in the list with the provided string value.
- 
showFilter Boolean[optional] show as filter when a value is selected in a global selected filters view. Defaults totrue.
- 
filterLabel String[optional] An optional label to display for the component in the global selected filters view. This is only applicable ifshowFilteris enabled. Default value used here iscomponentId.
- 
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 tofalse.
- 
showLoadMore Boolean[optional] defaults tofalseand works only with elasticsearch >= 6 since it uses composite aggregations. This adds a "Load More" button to load the aggs on demand combined with thesizeprop. 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 withshowLoadMore, you can only sort by:ascordescorder.sortByprop defaults toascwhenshowLoadMoreprop 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 torenderItem, where user can define how to render the view based on all the data changes.
 It accepts an object with these properties:- loading:- booleanindicates that the query is still in progress
- error:- objectAn object containing the error info
- data:- arrayAn array of results obtained from the applied query.
- rawData- objectAn object of raw response as-is from elasticsearch query.
- value:- stringcurrent selected value.
- handleChange:- functionA callback function can be used to mark the list value as selected.
- downshiftProps:- objectprovides all the control props from- downshiftwhich can be used to bind list items with click/mouse events. Read more about it here.
 
<SingleDropdownList
	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
<SingleDropdownList>
        {
            ({
                loading,
                error,
                data,
                value,
                handleChange,
                downshiftProps
            }) => (
                // return UI to be rendered
            )
        }
</SingleDropdownList>- 
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>}
- 
renderLabel Function[optional] can be used to change the label of the dropdown. Useful for adding highlighting/styling to or translating the label.renderLabel={(items) => Object.values(items).map((item) => ( <div> <MyTranslationComponent key={item} /> </div> ))}
- 
onChange function[optional] is a callback function which accepts component's current value as a parameter. It is called when you are using thevalueprops 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 theerrorobject, which can be used for debugging or giving feedback to the user if needed.
- 
index String[optional] The index prop can be used to explicitly specify an index to query against for this component. It is suitable for use-cases where you want to fetch results from more than one index in a single ReactiveSearch API request. The default value for the index is set to theappprop defined in the ReactiveBase component.Note: This only works when enableAppbaseprop is set to true inReactiveBase.
- 
isOpen boolean[optional] When set totruethe dropdown is displayed on the initial render. Defaults tofalse.
Demo
Styles
SingleDropdownList component supports innerClass prop with the following keys:
- title
- select
- list
- icon
- count
Read more about it here.
Extending
SingleDropdownList component can be extended to
- customize the look and feel with className,style,
- update the underlying DB query with customQuery,defaultQuery,
- connect with external interfaces using beforeValueChange,onValueChangeandonQueryChange,
- specify how options should be filtered or updated using reactprop.
<SingleDropdownList
  ...
  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 StringCSS class to be injected on the component container.
- 
style ObjectCSS styles to be applied to the SingleDropdownList component.
- 
customQuery Functiontakes 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 SingleDropdownList component as long as the component is a part ofreactdependency of at least one other component.
- 
defaultQuery Functiontakes 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 Functionis 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.Note: If you're using Reactivesearch version >= 3.3.7,beforeValueChangecan also be defined as a synchronous function.valueis updated by default, unless you throw anErrorto reject the update. For example:beforeValueChange = value => { // The update is accepted by default if (value === 'Dirk Pitt') { // To reject the update, throw an error throw Error('Selected value should not be equal to Dirk Pitt.'); } };
- 
onValueChange Functionis 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 a list item is selected in a "Discounted Price" SingleDropdownList.
- 
onQueryChange Functionis 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.
- 
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.
- 
react Objectspecify dependent components to reactively update SingleDropdownList's options.- key Stringone ofand,or,notdefines 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- Stringis used for specifying a single component by its- componentId.
- Arrayis used for specifying multiple components by their- componentId.
- Objectis used for nesting other key clauses.
 
 
- key