Typescript types for React Native's SectionList: A comprehensive guide

Question

Typescript types for React Native's SectionList: A comprehensive guide

Currently, I am in the process of developing a React Native app using TypeScript. In order to display information in a structured manner, I decided to implement a SectionList. Following the official documentation, I have written the following code snippet:

  renderSectionHeader = ({ section: { title } }: { section: { title: string } }) => (
    <ListItem title={title} />
  );

  render() {
    const { sections } = this.props;
    return (
      <SafeAreaView style={styles.container}>
        <SectionList
          keyExtractor={this.keyExtractor}
          sections={[
            {title: 'Title1', data: ['item1', 'item2']},
            {title: 'Title2', data: ['item3', 'item4']},
            {title: 'Title3', data: ['item5', 'item6']},
          ]}
          renderItem={this.renderItem}
          renderSectionHeader={this.renderSectionHeader}
        />
      </SafeAreaView>
    );
  }

However, upon adding the line

renderSectionHeader={this.renderSectionHeader}

, an unexpected TSLint Error is triggered:

[ts]
Type '({ section: { title } }: { section: { title: string; }; }) => Element' is not assignable to type '(info: { section: SectionListData<any>; }) => ReactElement<any> | null'.
  Types of parameters '__0' and 'info' are incompatible.
    Type '{ section: SectionListData<any>; }' is not assignable to type '{ section: { title: string; }; }'.
      Types of property 'section' are incompatible.
        Type 'SectionListData<any>' is not assignable to type '{ title: string; }'.
          Property 'title' is missing in type 'SectionListData<any>'. [2322]

This raises the question: Are there issues with the types associated with SectionList? Perhaps there is an error in the example provided? Or could it be possible that I have made a mistake in my implementation?

typescript react-native typescript-typings typescript-types react-native-sectionlist

Answer 1

Answer №1

let categories = [
  {name: 'Category1', items: ['itemA', 'itemB']},
  {name: 'Category2', items: ['itemC', 'itemD']},
  {name: 'Category3', items: ['itemE', 'itemF']},
];

To start, define the Category type and the Item type:

type Item = string;

type Category = {
  name: string;
  items: Item[];
};

Next, create your displayItem function:

const displayItem: SectionListRenderItem<Item, Category> = ({item}) => {
  // Add your component logic here
};

Answer 2

let categories = [
  {name: 'Category1', items: ['itemA', 'itemB']},
  {name: 'Category2', items: ['itemC', 'itemD']},
  {name: 'Category3', items: ['itemE', 'itemF']},
];

To start, define the Category type and the Item type:

type Item = string;

type Category = {
  name: string;
  items: Item[];
};

Next, create your displayItem function:

const displayItem: SectionListRenderItem<Item, Category> = ({item}) => {
  // Add your component logic here
};

Answer 3

Answer №2

Here is a solution that I found effective:

import type { SectionListData } from 'react-native';

interface CustomSection {
    title?: string;
    data: readonly any[];
}

type SectionHeaderComponent = (info: { section: SectionListData<YOUR_ARRAY_TYPE, CustomSection> }) => React.ReactElement;

const displaySectionHeader: SectionHeaderComponent = ({ section: { title } }) => {
    return YOUR_HEADER_COMPONENT;
};

Answer 4

Here is a solution that I found effective:

import type { SectionListData } from 'react-native';

interface CustomSection {
    title?: string;
    data: readonly any[];
}

type SectionHeaderComponent = (info: { section: SectionListData<YOUR_ARRAY_TYPE, CustomSection> }) => React.ReactElement;

const displaySectionHeader: SectionHeaderComponent = ({ section: { title } }) => {
    return YOUR_HEADER_COMPONENT;
};

Answer 5

Answer №3

I'm just starting out with TypeScript, so bear with me if this question isn't perfect. But for information on React Native types, you can refer to the following link: React Native Types on Github

At line 4243, you'll find this code snippet:

renderSectionHeader?: (info: { section: SectionListData<ItemT> }) => React.ReactElement<any> | null;

This indicates that the renderSectionHeader property requires a function with one argument, which is an object with a section field of type SectionListData<ItemT>.

To resolve the error you mentioned, you can make adjustments like this:

renderSectionHeader = ({ section: { title } }: { section: { title: string } }): React.ReactElement<any>=> (<ListItem title={title} />)

render() {
    const { sections } = this.props;
    return (
      <SafeAreaView style={styles.container}>
        <SectionList
          keyExtractor={this.keyExtractor}
          sections={[
            {title: 'Title1', data: ['item1', 'item2']},
            {title: 'Title2', data: ['item3', 'item4']},
            {title: 'Title3', data: ['item5', 'item6']},
          ]}
          renderItem={this.renderItem}
          renderSectionHeader={({section}: {section: SectionListData<string[]>}) => this.renderSectionHeader(section)}
        />
      </SafeAreaView>
    );
  }

I hope this solution works for you and resolves your issue.

EDIT: If you prefer not to specify types when passing props, this updated renderHeader method should work without errors:

renderSectionHeader = ({ section }: {section: SectionListData<string[]>}): ReactElement<any> | null => (<Text>{section.title}</Text>)

Answer 6

I'm just starting out with TypeScript, so bear with me if this question isn't perfect. But for information on React Native types, you can refer to the following link: React Native Types on Github

At line 4243, you'll find this code snippet:

renderSectionHeader?: (info: { section: SectionListData<ItemT> }) => React.ReactElement<any> | null;

This indicates that the renderSectionHeader property requires a function with one argument, which is an object with a section field of type SectionListData<ItemT>.

To resolve the error you mentioned, you can make adjustments like this:

renderSectionHeader = ({ section: { title } }: { section: { title: string } }): React.ReactElement<any>=> (<ListItem title={title} />)

render() {
    const { sections } = this.props;
    return (
      <SafeAreaView style={styles.container}>
        <SectionList
          keyExtractor={this.keyExtractor}
          sections={[
            {title: 'Title1', data: ['item1', 'item2']},
            {title: 'Title2', data: ['item3', 'item4']},
            {title: 'Title3', data: ['item5', 'item6']},
          ]}
          renderItem={this.renderItem}
          renderSectionHeader={({section}: {section: SectionListData<string[]>}) => this.renderSectionHeader(section)}
        />
      </SafeAreaView>
    );
  }

I hope this solution works for you and resolves your issue.

EDIT: If you prefer not to specify types when passing props, this updated renderHeader method should work without errors:

renderSectionHeader = ({ section }: {section: SectionListData<string[]>}): ReactElement<any> | null => (<Text>{section.title}</Text>)

Answer 7

Answer №4

define TypeData {
...
}

let NewSection = SectionList as SectionList<TypeData>;

<NewSection
...
/>

This solution worked perfectly for me!

Answer 8

define TypeData {
...
}

let NewSection = SectionList as SectionList<TypeData>;

<NewSection
...
/>

This solution worked perfectly for me!

Answer 9

Answer №5

If you want to get rid of the TSLint Error in this SectionListData declaration, all you need to do is replace the title property with key.

export interface SectionBase<ItemT> {
    data: ReadonlyArray<ItemT>;

    key?: string;

    renderItem?: SectionListRenderItem<ItemT>;

    ItemSeparatorComponent?: React.ComponentType<any> | null;

    keyExtractor?: (item: ItemT, index: number) => string;
}

export interface SectionListData<ItemT> extends SectionBase<ItemT> {
    [key: string]: any;
}

check out this image for more information

Answer 10

If you want to get rid of the TSLint Error in this SectionListData declaration, all you need to do is replace the title property with key.

export interface SectionBase<ItemT> {
    data: ReadonlyArray<ItemT>;

    key?: string;

    renderItem?: SectionListRenderItem<ItemT>;

    ItemSeparatorComponent?: React.ComponentType<any> | null;

    keyExtractor?: (item: ItemT, index: number) => string;
}

export interface SectionListData<ItemT> extends SectionBase<ItemT> {
    [key: string]: any;
}

check out this image for more information

Answer 11

Answer №6

import React from 'react';
import {SectionList, SectionListData, SectionListRenderItem, SectionListRenderItemInfo, Text} from 'react-native';

export type Item = string; // Updated data type

export type Section = {
  title: string;  // Updated section title
  data: readonly Item[];
}

type ListProps = {
  sections: SectionListData<Item, Section>[],
}

type RenderSectionHeaderArgs = {
  section: SectionListData<Item, Section>
}

const renderSectionItem: SectionListRenderItem<Item> = ({item}) => {
  console.log(item);
  return <Text>{item}</Text>;
};

const renderSectionHeader = ({section: {title, data}}: RenderSectionHeaderArgs) => {
  console.log({title, data});
  return <Text>{title}</Text>;
};

const List: React.FC<ListProps> = ({sections}) => {
  return (
    <SectionList
      sections={sections}
      renderItem={renderSectionItem}
      renderSectionHeader={renderSectionHeader}
    />
  );
};

export default List;

Answer 12

import React from 'react';
import {SectionList, SectionListData, SectionListRenderItem, SectionListRenderItemInfo, Text} from 'react-native';

export type Item = string; // Updated data type

export type Section = {
  title: string;  // Updated section title
  data: readonly Item[];
}

type ListProps = {
  sections: SectionListData<Item, Section>[],
}

type RenderSectionHeaderArgs = {
  section: SectionListData<Item, Section>
}

const renderSectionItem: SectionListRenderItem<Item> = ({item}) => {
  console.log(item);
  return <Text>{item}</Text>;
};

const renderSectionHeader = ({section: {title, data}}: RenderSectionHeaderArgs) => {
  console.log({title, data});
  return <Text>{title}</Text>;
};

const List: React.FC<ListProps> = ({sections}) => {
  return (
    <SectionList
      sections={sections}
      renderItem={renderSectionItem}
      renderSectionHeader={renderSectionHeader}
    />
  );
};

export default List;

Answer 13

Answer №7

In the event that you are familiar with the types being used and simply want to prevent the warning, you have the option to use the following approach:

segments = {segments as any[]}

Answer 14

In the event that you are familiar with the types being used and simply want to prevent the warning, you have the option to use the following approach:

segments = {segments as any[]}

Typescript types for React Native's SectionList: A comprehensive guide

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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