Info

This package provides a single React component. The component contains an input field with a drop down menu to pick a possible option based on the current input as a React component.

Have a look at w3schools.com to see how you can do something similar with pure html, css, and js. For more information about React and the ecosystem see this guide.

Demo

Check it out on my personal website!

Feedback

Feel free to get inspired and more importantly please provide your feedback on structure and style.

Using Gatsby or Next.js?

This component is not compatible with server-side rendering since it has css bundled with it.

I created a plain version of this package without css. Find more information here.

Versions

• Version 2.x.x serves a functional component using hooks
• Version 1.x.x serves a class component

The documentation below mainly applies for both versions but will be updated based on version 2.x.x updates in the future.

Installation

Installation via npm

npm i react-datalist-input

Basic Usage

import React, { useState, useMemo, useCallback } from "react";
import DataListInput from "react-datalist-input";

const YourComponent = ({ myValues }) => {
  // selectedItem
  const [item, setItem] = useState();

  /**
   * your callback function gets called if the user selects one option out of the drop down menu
   * @param selectedItem object (the selected item / option)
   */
  const onSelect = useCallback((selectedItem) => {
    console.log("selectedItem", selectedItem);
  }, []);

  // the array you want to pass to the react-data-list component
  // key and label are required properties
  const items = useMemo(
    () =>
      myValues.map((oneItem) => ({
        // required: what to show to the user
        label: oneItem.name,
        // required: key to identify the item within the array
        key: oneItem.id,
        // feel free to add your own app logic to access those properties in the onSelect function
        someAdditionalValue: oneItem.someAdditionalValue,
        // or just keep everything
        ...oneItem,
      })),
    [myValues]
  );

  return (
    <DataListInput
      placeholder="Select an option from the drop down menu..."
      items={items}
      onSelect={onSelect}
    />
  );
};

Properties

Prop	Type	Required/Optional	Default Value
items	array	required	-
onSelect	function	required	-
match	function	optional	internal matching function
onDropdownOpen	function	optional	-
onDropdownClose	function	optional	-
placeholder	string	optional	''
itemClassName	string	optional	-
activeItemClassName	string	optional	-
inputClassName	string	optional	-
dropdownClassName	string	optional	-
requiredInputLength	number	optional	0
clearInputOnSelect	boolean	optional	false
suppressReselect	boolean	optional	true
dropDownLength	number	optional	infinite
initialValue	string	optional	-
debounceTime	number	optional	0
debounceLoader	string	optional	'Loading...'
onInput	function	optional	-

items

• Required property!
• The array of options for the drop down menu.
  
• Every item inside the array needs to have following properties:
  • key : an id that identifies the item within the array
  • label: the label that will be shown in the drop down menu

onSelect

• Required property!
• The callback function that will be called if the user selects one item of the drop down menu.
• Gets only called if the item changes. Selecting the same item twice will only trigger the function once (the first time).
• Parameter: (selectedKey)
  • selectedKey: the Key Property of the item that the user selected

match

• Pass a match function as stated above for creating your own matching algorithm for the autocomplete functionality.

• Parameter: (currentInput, item)

  • currentInput: String, the current user input typed into the input field
  • item: Object, the item of the items array (with key and label properties)

• Default:

/**
 * default function for matching the current input value (needle) and the values of the items array
 * @param currentInput String (the current user input)
 * @param item (one item of the items array)
 * @returns {boolean}
 */
match = (currentInput, item) => {
  return (
    item.label.substr(0, currentInput.length).toUpperCase() ===
    currentInput.toUpperCase()
  );
};

onDropdownOpen

• The callback function that will be called after opening the drop down menu.
• It will fire only once and not be called again after new input.

onDropdownClose

• The callback function that will be called after closing the drop down menu.

placeholder

• The placeholder that will be shown inside the input field.
• Default is an empty string

itemClassName

• Additional classes to style each input field in the dropdown menu.
• Default is an empty string
• Removes the default styling if set

activeItemClassName

• Additional classes to style the active input field.
• Default is an empty string
• Removes the default styling if set

inputClassName

• Additional classes to style the input field.
• Default is an empty string
• Removes the default styling if set

dropdownClassName

• Additional classes to style the dropdown box.
• Default is an empty string
• Adds on the required styling (e.g. position:absolute)
• Removes the default styling if set

requiredInputLength

• Number to specify the threshold until when the dropdown menu should appear.
• Example requiredInputLength=3, only if the user input is longer than 2 characters, the dropdown menu will appear.
• Default is zero.

clearInputOnSelect

• Should the input field be cleared on select on filled with selected item?
• Default is false.

suppressReselect

• If suppressReselect is set to false, selecting the same item again, it will trigger another onSelect callback call.
• Default is true.

dropDownLength

• Only display the first dropDownLength matches in the dropdown. Useful if the array is really big.
• Number to specify max length of drop down.
• Default is Infinity.

initialValue

• Specify an initial value for the input field.
• For example, initialValue={'hello world'} will print hello world into the input field on first render.
• Default is empty string.
• Caution: Don't confuse this with a placeholder (see placerholder prop), this is an actual value in the input and supports uses cases like saving user state or suggesting a search value.

debounceTime

• Use debounceTime to define a debounce timeout time (in milliseconds) before the matching algorithm should be called
• New user input will trigger a new call to the debounce step and will clear every unresolved timeout
• For example, debounceTime={1000} will call the matching algorithm one second after the last user input
• This is useful if items is very large and/or the match-algorithm is doing some heavier operations
• debounceTime may improve the user experience by reducing lag times as it reduces the calls to the matching and rendering of the dropdown.
• Be careful, using too much debounceTime will slow down the response time of this component.
• If you still have performance issues even when using a debounceTime={3000} or higher, you might want to consider using another package / user input instead. Think about a "search/look-up"-button next to your input field or even consider running the search functionality in a dedicated backend.
• Default is zero which means no timeout/debouncing is used.

debounceLoader

• Only in use if debounceTime is set
• Of type node which can be anything that react can render and will be shown as a loading bar
• Default is string "loading...".

onInput

• The callback function that will be called whenever the user types into the input field
• Exposing this function supports use cases like resetting states on empty input field