@cogitojs/cogito-ethereum-react

@cogitojs/cogito-ethereum-react

Provides a React component that allows interaction with smart contracts on an Ethereum blockchain using the Cogito app. It provides the same functionality as the Cogito Ethereum package in a React friendly way.

Usage

Add @cogitojs/cogito-ethereum-react as a dependency:

yarn add @cogitojs/cogito-ethereum-react

and import it:

import { CogitoEthereumReact } from '@cogitojs/cogito-ethereum-react'

Props

The CogitoEthereumReact component accepts the following props:

prop name	description
contractsBlobs	Array of contracts JSON blobs - see Working with Contracts for more details.
channelId	identifier of the Telepath channel. If omitted a new random channel id will be created.
channelKey	a symmetric key of the Telepath channel. If omitted a new random key will be created.
appName	the name of the app. Cogito app shows the appName when requesting user signature.
onTelepathChanged	function to be called when the telepath channel has been updated. Provides an object { channelId, channelKey, appName } as an argument.
render	render prop - a function that will be called every time the component is updated. It provides { cogitoWeb3, telepathChannel, contractsProxies, newChannel } as an argument, where cogitoWeb3 is an instance of Web3 that uses CogitoProvider, telepathChannel is an instance of Telepath, and contractsProxies is an object holding the references to contracts proxies corresponding to the provided contracts JSON blobs (see Working with Contracts for details). newChannel is a function to change the current channel to a new one. This function will trigger calling the render prop (or child) function, which means the whole tree below it will be (re)rendered. If this prop is present, it will take precedence over the children.

Example

The example below illustrates how to use the CogitoEthereumReact component:

import { CogitoEthereumReact } from '@cogitojs/cogito-ethereum-react'
import { SimpleStorage } from '@cogitojs/demo-app-contracts'

class Main extends React.Component {
  web3IsReady = ({cogitoWeb3, telepathChannel, contractsProxies}) => {
    return (cogitoWeb3 && telepathChannel && contractsProxies.SimpleStorage)
  }

  onTelepathChanged = ({ channelId, channelKey, appName }) => {
    console.log('Telepath channel changed:')
    console.log(`channelId: ${channelId}`)
    console.log(`channelKey: ${channelKey}`)
    console.log(`appName: ${appName}`)
  }

  render () {
    return (
      <CogitoEthereumReact contractsBlobs={[SimpleStorage()]}
        channelId={channelId}
        channelKey={channelKey}
        appName='Cogito Demo App'
        onTelepathChanged={this.onTelepathChanged}
      >
        {web3Props => {
          if (this.web3IsReady(web3Props)) {
            return (
              <div>
                <p>Ready!</p>
                <button onClick={web3Props.newChannel()}>
                  Change channel
                </button>
              </div>
            )
          } else {
            return (
              <p>Please wait...</p>
            )
          }
        }}
      </CogitoEthereumReact>
    )
  }
}

export { Main }

If you prefer using render prop, the render method would look like this:

render () {
  return (
    <CogitoEthereumReact contractsBlobs={[SimpleStorage()]}
      channelId={channelId}
      channelKey={channelKey}
      appName='Cogito Demo App'
      onTelepathChanged={this.onTelepathChanged}
      render={web3Props => {
        if (this.web3IsReady(web3Props)) {
          return (
            <div>
              <p>Ready!</p>
              <button onClick={web3Props.newChannel()}>
                Change channel
              </button>
            </div>
          )
        } else {
          return (
            <p>Please wait...</p>
          )
        }
      }} />
  )
}