Salesforce Lookup Component

About
Installation
Documentation
Reference

About

This is a generic & customizable lookup component built using Salesforce Lightning Web Components and SLDS style.
It does not rely on third party libraries and you have full control over its datasource.

Features

The lookup component provides the following features:

customizable data source that can return mixed sObject types
single or multiple selection mode
client-side caching & request throttling
built-in server request rate limit mechanism
project is unit tested

Installation

The default installation installs the lookup component and a sample application available under this URL (replace the domain):
https://YOUR_DOMAIN.lightning.force.com/c/SampleLookupApp.app

If you wish to install the project without the sample application, edit sfdx-project.json and remove the src-sample path.

Install the sample app by running this script:

MacOS or Linux

./install-dev.sh

Windows

install-dev.bat

Documentation

Getting Started

Follow these steps in order to use the lookup component:

Write the search endpoint

Implement an Apex @AuraEnabled(Cacheable=true) method (SampleLookupController.search in our samples) that returns the search results as a List<LookupSearchResult>. The method name can be different but it needs to match this signature:
```
@AuraEnabled(Cacheable=true)
public static List<LookupSearchResult> search(String searchTerm, List<String> selectedIds) {}
```
Import a reference to the search endpoint

Import a reference to the search Apex method in the lookup parent component's JS:
```
import apexSearch from '@salesforce/apex/SampleLookupController.search';
```

Handle the search event and pass search results to the lookup

The lookup component exposes a search event that is fired when a search needs to be performed on the server-side. The parent component that contains the lookup must handle the search event:

<c-lookup onsearch={handleSearch} label="Search" placeholder="Search Salesforce">
</c-lookup>

The search event handler calls the Apex search method and passes the results back to the lookup using the setSearchResults(results) function:

handleSearch(event) {
    const target = event.target;
    apexSearch(event.detail)
        .then(results => {
            target.setSearchResults(results);
        })
        .catch(error => {
            // TODO: handle error
        });
}

Handling selection changes (optional)

The lookup component exposes a selectionchange event that is fired when the selection of the lookup changes. The parent component that contains the lookup can handle the selectionchange event:

<c-lookup onsearch={handleSearch} onselectionchange={handleSelectionChange}
    label="Search" placeholder="Search Salesforce">
</c-lookup>

The selectionchange event handler can then get the current selection form the event detail or by calling the getSelection() function:

handleSelectionChange(event) {
    // Get the selected ids from the event (same interface as lightning-input-field)
    const selectedIds = event.detail;
    // Or, get the selection objects with ids, labels, icons...
    const selection = event.target.getSelection();
    // TODO: do something with the lookup selection
}

getSelection() always return a list of selected items. That list contains a maximum of one element if the lookup is a single-entry lookup.

Providing default search results (optional)

The lookup can return default search results with the setDefaultResults(results) function. This is typically used to return a list of recently viewed records (see sample app).

Here's how you can retrieve recent records and set them as default search results:

Implement an Apex endpoint that returns the recent records:
```
@AuraEnabled(Cacheable=true)
public static List<LookupSearchResult> getRecentlyViewed()
```
See the full code from the sample app
In your parent component, create a property that holds the default results:
```
recentlyViewed = [];
```

Write a utility function that sets your default search results:

initLookupDefaultResults() {
    // Make sure that the lookup is present and if so, set its default results
    const lookup = this.template.querySelector('c-lookup');
    if (lookup) {
        lookup.setDefaultResults(this.recentlyViewed);
    }
}

Retrieve the recent records by calling your endpoint:

@wire(getRecentlyViewed)
getRecentlyViewed({ data }) {
    if (data) {
        this.recentlyViewed = data;
        this.initLookupDefaultResults();
    }
}

Initialize the lookup default results when the parent component loads:
```
connectedCallback() {
    this.initLookupDefaultResults();
}
```

Note: initLookupDefaultResults() is called in two places because the wire could load before the lookup is rendered.

Reference

Attributes

Attribute	Type	Description
`label`	`String`	Optional lookup label. Label is hidden if attribute is omitted.
`selection`	`[LookupSearchResult]` OR `LookupSearchResult`	Lookup initial selection if any. Array for multi-entry lookup or an Object for single entry lookup.
`placeholder`	`String`	Lookup placeholder text
`isMultiEntry`	`Boolean`	Whether the lookup is single (default) or multi entry.
`required`	`Boolean`	Whether the lookup is a required field. Note: Property can be set with `<c-lookup required>`.
`errors`	`[{ "id": String, "message": String }]`	List of errors that are displayed under the lookup.
`scrollAfterNItems`	`Number`	A null or integer value used to force overflow scroll on the result listbox after N number of items. Valid values are null, 5, 7, or 10. Use null to disable overflow scrolling.

Functions

Function	Description
`setDefaultResults(results)`	Allows to set optional default items returned when search has no result (ex: recent items). `results` is an array of `LookupSearchResult`.
`setSearchResults(results)`	Passes a search result array back to the lookup so that they are displayed in the dropdown. `results` is an array of `LookupSearchResult`.
`getSelection()`	Gets the current lookup selection as an array of `LookupSearchResult`.

Events

Event	Description	Data
`search`	Event fired when a search needs to be performed on the server-side.	`{ searchTerm: String, selectedIds: [ String ] }`
`selectionchange`	Event fired when the selection of the lookup changes. Selection ids are in the event details. You can also use `target.getSelection()` to retrieve the selected lookup objects.	`{ detail: [ String ] }`

billv5w/sfdc-ui-lookup-lwc