Streamr-client-react ✨

React hooks and components for @streamr/sdk.

Installation

Using npm, install the library, and save it to your package.json dependencies.

npm i streamr-client-react

The library relies on a collection of peer dependencies:

process ^0.11.10
react >=16.8.0
react-fast-compare ^3.2.0
@streamr/sdk >= 100.0.0

Make sure you install them, too!

API

Components

Provider

It holds its own StreamrClient instance and – by utilizing the Context API – makes it available to all its children components.

import Provider from 'streamr-client-react'

function App() {
    return <Provider {...options}>You can use `useClient` here!</Provider>
}

---

ClientContext

If you wanna hack your way around the useClient hook for some wholesome reason and directly access the client instance provided by the Provider component this is where you start.

import { useContext } from 'react'
import type { StreamrClient } from '@streamr/sdk'
import { ClientContext } from 'streamr-client-react'

function SqrtOfFoo() {
    const client: undefined | StreamrClient = useContext(ClientContext)

    return null
}

Hooks

useClient(config?: StreamrClientConfig)

import { useClient } from 'streamr-client-react'

If config is given, useClient gives you a new instance of the client. The hook uses react-fast-compare to avoid unreasonable creation of new instances.

If config is skipped, it's gonna return an instance provided by the Provider component (undefined by default).

See Config.ts for more details on StreamrClientConfig.

---

useSubscribe(streamId: string, options?: Options)

import { useSubscribe } from 'streamr-client-react'

It allows you to conveniently subscribe to streams.

import type { ResendOptions, StreamMessage } from '@streamr/sdk'

interface Options {
    // Changing `cacheKey` will drop the old subscription and start a new one.
    cacheKey?: number | string
    // Set `disabled` to true to make it idle, or to make it drop the previous subscription
    // and then idle.
    disabled?: boolean
    // You can either skip undecoded messages (true), or treat them as other messages (false), and
    // handle their undecoded content on your own. Useful when you have to show "something".
    // Default: false
    ignoreUndecodedMessages?: boolean
    // A callback triggered after you're done with a subscription and with processing messages.
    onAfterFinish?: () => void
    // A callback triggered before subscribing.
    onBeforeStart?: () => void
    // A callback triggered when the client fails at subscribing.
    onError?: (e: any) => void
    // *The* on-message callback.
    onMessage?: (msg: StreamMessage) => void
    // A callback triggered when the client fails to decode a massage.
    onMessageError?: (e: any) => void
    // Resend instructions. `undefined` by default (= don't resend anything).
    resendOptions?: ResendOptions
}

onAfterFinish, onBeforeStart, onError, onMessage, and onMessageError are all kept as refs (see useRef) internally, and for that reason changing them does not trigger resubscribing. Additionally, we track changes to resendOptions using react-fast-compare to avoid excessive resubscribing.

See

• client/src/subscribe/Resends.ts for more details on ResendOptions.

---

useResend(streamId: string, resendOptions: ResendOptions, options?: Options)

import { useResend } from 'streamr-client-react'

It allows you to resend historical messages without subscribing to the real-time messages.

import type { ResendOptions, Message } from '@streamr/sdk'

interface Options {
    // Changing `cacheKey` will drop the old subscription and start a new one.
    cacheKey?: number | string
    // Set `disabled` to true to make it idle, or to make it drop the previous subscription
    // and then idle.
    disabled?: boolean
    // You can either skip undecoded messages (true), or treat them as other messages (false), and
    // handle their undecoded content on your own. Useful when you have to show "something".
    // Default is false.
    ignoreUndecodedMessages?: boolean
    // A callback triggered after you're done with a subscription and with processing messages.
    onAfterFinish?: () => void
    // A callback triggered before subscribing.
    onBeforeStart?: () => void
    // A callback triggered when the client fails at subscribing.
    onError?: (e: any) => void
    // *The* on-message callback.
    onMessage?: (msg: Message) => void
    // A callback triggered when the client fails to decode a massage.
    onMessageError?: (e: any) => void
}

See

• client/src/subscribe/Resends.ts for more details on ResendOptions.
• client/src/Message.ts for more details on Message.

Utils

subscribe(streamId: string, client: StreamrClient, options?: Options)

import { subscribe } from 'streamr-client-react'

Subscribes to a stream and returns an object with 2 asynchrounous methods: next and abort. Example:

async function foo(streamId: string, client: StreamrClient) {
    const queue = subscribe(streamId, client)

    while (true) {
        const { value: msg, done } = await queue.next()

        if (msg) {
            // Do something with a message here.
        }

        if (done) {
            break
        }
    }

    // Use `queue.abort()` to unsubscribe.
}

Available options:

interface Options {
    // You can either skip undecoded messages (true), or treat them as other messages (false), and
    // handle their undecoded content on your own. Useful when you have to show "something".
    // Default is false.
    ignoreUndecodedMessages?: boolean
    // A callback triggered when the client fails at subscribing.
    onError?: (e: any) => void
    // Resend instructions. `undefined` by default (= don't resend anything).
    onMessageError?: (e: any) => void
}

---

resend(streamId: string, resendOptions: ResendOptions, streamrClient: StreamrClient, options?: Options)

import { resend } from 'streamr-client-react'

Subscribes to a stream of historical messages (only) and returns an object with 2 asynchrounous methods: next and abort. Example:

async function foo(streamId: string, client: StreamrClient) {
    const queue = resend(streamId, { last: 10 }, client)

    while (true) {
        const { value: msg, done } = await queue.next()

        if (msg) {
            // Do something with a message here.
        }

        if (done) {
            break
        }
    }

    // Use `queue.abort()` to ignore further data.
}

subscribe and resend share the options.