0.2.0 • Published 7 years ago

react-native-controlled-listview v0.2.0

Weekly downloads
1
License
MIT
Repository
github
Last release
7 years ago

Why?

For performance reasons, React Native ListView needs a ListView.DataSource, so it can efficiently update itself. To benefit from these optimisations, any component wishing to render a ListView needs to be stateful to hold the DataSource, and faff about with lifecycle methods to update it.

This library hides that statefulness and provides a simple, props-based API to render ListViews.

How-to

Installation:

npm i --save react-native-controlled-listview

Instead of dataSource, controlled ListView expects an array prop items. Optionally, you can sort the list with sortBy or group it into sections with sectionBy:

- import { ListView } from 'react-native';
+ import ListView from 'react-native-controlled-listview';

// stateless function component
export default (props) => (
+ <ListView
-   dataSource=...
+   items={props.people}
+   sortBy={(person) => person.lastName}
+   sectionBy={(person) => person.lastName[0]}
    renderRow={(person) => (
      <Text style={styles.row}>{person.lastName}, {person.firstName}</Text>
    )}
    renderSectionHeader={(sectionData, initial) => (
      <Text style={styles.sectionHeader}>{initial}</Text>  
    )}
  />
);

Immutability

There is one gotcha. This component expects you to clone the items prop when you want to ListView to update. If you are using Redux, this should already be the case.

The items prop can be an instance of Immutable.List, or an array. If using plain arrays, never mutate it in-place, or the ListView won't update.

See dataSourceShouldUpdate on how to customise the update logic.

Props

items : any[] | Immutable.List (required)

List data source.

sortBy : (a, b) => number | boolean

Sorts the list based on a comparator. Value can be one of type:

  • (a, b) => number a standard Array#sort compareFunction.
  • (a, b) => boolean a shorthand comparator: if returns true, a comes first; if false, b comes first.
sectionBy : (a, b) => string

Groups the list based on returned value and renders section headers for each group.

If using sectionBy, you must also provide renderSectionHeader

rowHasChanged : (prevItem, nextItem) => boolean

Passed directly to ListView.DataSource. constructor. Defaults to !Immutable.is(prevItem, nextItem), which performs a === comparison for plain objects.

sectionHeaderHasChanged : (prevSectionData, nextSectionData) => boolean

Passed directly to ListView.DataSource. constructor. Defaults to prev !== next.

dataSourceShouldUpdate : (prevProps, nextProps) => boolean

Controls when the data source should be updated. The default implementation is !Immutable.is(prevProps.items, nextProps.items), which performs a === comparison for plain arrays.

...ListView.props

All other properties, except dataSource are passed directly to the underlying ListView.

Please note

This project is in a pre-release state. The API may be considered relatively stable, but changes may still occur.

MIT licensed