piaskowyk / flash-list

A better list for React Native

Website • Discord • Getting started • Usage • Performance • Writing performant components • Known Issues

Fast & performant React Native list. No more blank cells.

Swap from FlatList in seconds. Get instant performance.

Installation

Add the package to your project via yarn add @shopify/flash-list and run pod install in the ios directory.

If you get the error Plugin with id 'kotlin-android' not found while building on Android, go to android/build.gradle and add classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.0") inside your dependencies block. Please change the plugin version as per your needs.

Usage

We recommend reading the detailed documentation for using FlashList here.

But if you are familiar with FlatList, you already know how to use FlashList. You can try out FlashList by changing the component name and adding the estimatedItemSize prop or refer to the example below:

import React from "react";
import { View, Text } from "react-native";
import { FlashList } from "@shopify/flash-list";

const DATA = [
  {
    title: "First Item",
  },
  {
    title: "Second Item",
  },
];

const MyList = () => {
  return (
    <FlashList
      data={DATA}
      renderItem={({ item }) => <Text>{item.title}</Text>}
      estimatedItemSize={200}
    />
  );
};

To avoid common pitfalls, you can also follow these steps for migrating from FlatList, based on our own experiences:

1. Switch from FlatList to FlashList and render the list once. You should see a warning about missing estimatedItemSize and a suggestion. Set this value as the prop directly.
2. Important: Scan your renderItem hierarchy for explicit key prop definitions and remove them. If you’re doing a .map() use indices as keys.
3. If your list has heterogenous views, pass their types to FlashList using getItemType prop to improve performance.
4. Do not test performance with JS dev mode on. Make sure you’re in release mode. FlashList can appear slower while in dev mode due to a small render buffer.

App / Playground

The fixture is an example app showing how to use the library.