
MultiList creates a multiple selection based list UI component that is connected to a database field. It is similar to a SingleList except it can support multiple item selections.
Example uses:
- select category items from a list of categories in an e-commerce website.
 - selecting airlines to fly by in a flight booking experience.
 
Usage
Basic Usage
<template>
	<multi-list componentId="CitySensor" dataField="group.group_city.raw" title="Cities" />
</template>Usage With All Props
<template>
	<multi-list
		componentId="CitySensor"
		dataField="group_city.raw"
		title="Cities"
		sortBy="asc"
		queryFormat="or"
		selectAllLabel="All Cities"
		placeholder="Search City"
		filterLabel="City"
		:showFilter="true"
		:showCheckbox="true"
		:showCount="true"
		:showSearch="true"
		:defaultValue="['San Francisco']"
		:react="{ and: ['CategoryFilter', 'SearchFilter'] }"
		:size="100"
		:URLParams="false"
	/>
</template>Props
- 
componentId
Stringunique identifier of the component, can be referenced in other components'reactprop. - 
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. Defaults to no title being shown. - 
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] sort the list items by one ofcount,asc, ordesc. Defaults tocount, which sorts the list by the frequency of count value, most first. - 
defaultValue
Array[optional] pre-select one or more list items. Accepts anArrayobject containing the items that should be selected. It is important for the passed value(s) to exactly match the field value(s) as stored in the DB. - 
value
Array<String>[optional] sets the current value of the component. It sets the value (on mount and on update). Use this prop in conjunction with thechangeevent. - 
queryFormat
String[optional] queries the selected items from the list in one of two modes:or,and.- Defaults to 
orwhich queries for results where any of the selected list items are present. - In 
andmode, the applied query filters results where all of the selected items are present. 
 - Defaults to 
 - 
selectAllLabel
String[optional] add an extraSelect allitem to the list with the provided label string. - 
showCheckbox
Boolean[optional] show checkbox icon for each list item. Defaults totrue. - 
showCount
Boolean[optional] show a count of the number of occurences besides each list item. Defaults totrue. - 
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. - 
renderItem
Function|slot-scope[optional] customize the rendered list via a function or slot-scope which receives the item label, count and isChecked & expects a JSX or String back. For example: 
<multi-list>
	<div
        slot="renderItem"
        slot-scope="{ label, count }"
    >
		{{label}}
		<span :style="{ marginLeft: 5, color: 'dodgerblue' }">
			{{count}}
		</span>
	</div>
</multi-list>- 
render
Function|slot-scope[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 progresserror:objectAn object containing the error infodata:arrayAn array of results obtained from the applied query.rawDataobjectAn object of raw response as-is from elasticsearch query.value:arraycurrent selected values.handleChange:functionA callback function can be used to mark the list value as selected.
 
You can use render as a slot as shown below:
<multi-list
    :showSearch="false"
    componentId="BookSensor"
    data-field="original_series.raw"
>
	<div
        class="suggestions"
        slot="render"
        slot-scope="{ data, handleChange }"
    >
		<ul>
			<li
				style="{ background-color: highlightedIndex ? 'grey' : 'transparent' }"
				v-for="suggestion in (data || [])"
				:key="suggestion._id"
				v-on:click="handleChange(suggestion.key)"
			>
				{{ suggestion.key }}
			</li>
		</ul>
	</div>
</multi-list>- renderError 
String|Function|slot-scope[optional] can be used to render an error message in case of any error. 
<template
    slot="renderError"
    slot-scope="error"
>
	<div>Something went wrong!<br />Error details<br />{{ error }}</div>
</template>- renderNoResults 
String|Function|slot-scope[optional] show custom message or component when no results found. 
<template
    slot="renderNoResults"
>
	<h4>No Results Found!</h4>
</template>
<!-- or -->
<multi-list
	...
	:renderNoResults="renderNoResults"
/>
export default {
	...,
	method: {
		renderNoResults() {
			return 'Try Again';
		}
	},
}
- transformData 
Function[optional] allows transforming the data to render inside the list. You can change the order, remove, or add items, transform their values with this method. It provides the data as param which is an array of objects of shape { key:, doc_count: } and expects you to return the array of objects of same shape.  - 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. - showSearch 
Boolean[optional] whether to show a searchbox to filter the list items locally. Defaults to true. - placeholder 
String[optional] placeholder to be displayed in the searchbox, only applicable when theshowSearchprop is set totrue. When applicable, the default placeholder value is set to "Search". - 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. 
Demo
Styles
MultiList component supports innerClass prop with the following keys:
titleinputlistcheckboxlabelcount
Read more about it here.
Extending
MultiList component can be extended to
- customize the look and feel with 
className, - update the underlying DB query with 
customQuery, - connect with external interfaces using 
beforeValueChange,value-changeandquery-change, - specify how options should be filtered or updated using 
reactprop. 
<template>
	<multi-list
		className="custom-class"
		:customQuery="getCustomQuery"
		:react="react"
		:beforeValueChange="handleBeforeValueChange"
		@value-change="handleValueChange"
		@query-change="handleQueryChange"
	/>
</template>
<script>
	export default {
		name: 'app',
		methods: {
			getCustomQuery: (value, props) => {
				return {
					query: {
						match: {
							data_field: 'this is a test',
						},
					},
				};
			},
			handleBeforeValueChange: value => {
				// called before the value is set
				// returns a promise
				return new Promise((resolve, reject) => {
					// update state or component props
					resolve();
					// or reject()
				});
			},
			handleValueChange: value => {
				console.log('current value: ', value);
				// set the state
				// use the value with other js code
			},
			handleQueryChange: (prevQuery, nextQuery) => {
				// use the query with other js code
				console.log('prevQuery', prevQuery);
				console.log('nextQuery', nextQuery);
			},
		},
		computed: {
			react() {
				return {
					and: ['pricingFilter', 'dateFilter'],
					or: ['searchFilter'],
				};
			},
		},
	};
</script>- 
className
StringCSS class to be injected on the component container. - 
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 MultiList component as long as the component is a part ofreactdependency of at least one other component.Note:When extending with customQuery, thequeryFormatprop has no affect. - 
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.Note:defaultQuery doesn't get leaked to other components. - 
beforeValueChange
Functionis a callback function which accepts component's future value as a parameter and returns a promise. It is called every time 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 >=
1.1.0,beforeValueChangecan also be defined as a synchronous function.valueis updated by default, unless you throw anErrorto reject the update. For example:beforeValueChange = values => { // The update is accepted by default if (values.includes('Dirk Pitt')) { // To reject the update, throw an error throw Error('Selected values should not include Dirk Pitt.'); } }; - 
react
Objectspecify dependent components to reactively update MultiList'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 ObjectStringis used for specifying a single component by itscomponentId.Arrayis used for specifying multiple components by theircomponentId.Objectis used for nesting other key clauses.
 
 - key 
 - 
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. 
Events
- 
change is an event that accepts component's current value as a parameter. It is called when you are using the
valueprop and the component's value changes. This event is useful to control the value updates of search input.<template> <multi-list // ...other props value="value" @change="handleChange" /> </template> <script> export default { name: 'app', data() { return { value: [] } }, methods: { handleChange(value) { this.value = value; } } }; </script> - 
query-change is an event which accepts component's prevQuery and nextQuery as parameters. It is called everytime the component's query changes. This event is handy in cases where you want to generate a side-effect whenever the component's query would change.
 - 
value-change is an event which accepts component's current value as a parameter. It is called everytime the component's value changes. This event 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" SingleList.
 - 
error gets triggered in case of an error and provides the
errorobject, which can be used for debugging or giving feedback to the user if needed.