Emblock-sdk-js NPM

emblock-sdk-js: Emblock.co SDK for Javascript

emblock-sdk-js is a sdk for the Emblock.co platform, it can be used on client and server side.

Please check out our website before using our sdk.

Installing

npm install emblock-sdk-js

API docs

See /doc/emblock-sdk-js.md for Node.js-like docs for the emblock-sdk-js classes.

Usage examples

Creating an instance of EmblockClient

const EmblockClient = require('emblock-sdk-js').default
const emblock = new EmblockClient('<API_KEY>', '<YOUR_PROJECT_ID>')

Calling a constant function or get a state value

// { paramName1: "<param_value_1>", paramName2: "<param_value_2>" }
const params = { owner: '0xcd92C45083aB059B1e5Af91c7cE58adf9D199e3c' }
emblock
  .callConstant('balanceOf', params)
  .then(result => {
    // result = [{"type": "uint256", "value": "100", "name": "balance"}]
    // type = type of the result
    // value = value of the result
    // name = name of the result (can be null)
    console.log('data=' + JSON.stringify(result))
  })
  .catch(err => {
    console.log('error=' + err)
  })

Calling a function

We are calling the transfer function of an ERC-20 smart contract.

const user1 = '0x73426F686Db8e511310a9fb90F9B22DB71ed53D4' // wallet address of the user 1
var wallet = '0xcd92C45083aB059B1e5Af91c7cE58adf9D199e3c' // wallet address of the sender
const params = { to: user1, value: '100' }
emblock
  .callFunction(wallet, 'transfer', params)
  .then(resp => {
    if (resp.isSuccessful) console.log('successful')
    else console.log('failed')
  })
  .catch(err => {
    console.log('error=' + err)
  })

Call a function with client-side signature

We are calling the transfer function of an ERC-20 smart contract. The transaction is signed on client side with the given privateKey. It returns the signature in hex format.

const user1 = '0x73426F686Db8e511310a9fb90F9B22DB71ed53D4' // wallet address of the user 1
const params = { to: user1, value: '100' }
const privateKey = '<sender_private_key>'
const publicKey = '<sender_public_key>'
emblock
  .getFunctionCallSignature(publicKey, privateKey, 'transfer', params)
  .then(resp => {
    console.log('signature=' + resp)

    // ... then eth_sendRawTransaction
  })
  .catch(err => {
    console.log('error=' + err)
  })

Listening to Events

Listening to events emitted by your smart contract.

emblock.addEventsListener(({ event, params, error }) => {
  if (error) {
    console.log('error=' + error)
  } else {
    if (event === 'Transfer') {
      console.log('this is a Transfer event !')
    }
  }
})