Web3Singletone template

Web3Factory.ts

import Web3 from 'web3'
import Window from './window'

// Singletone Class
class Web3Factory {
  public web3: Web3
  private static _instance: Web3Factory

  // Private Constructor
  private constructor(window: Window) {
    if (window.ethereum) {
      this.getPermissionFromMetabask(window.ethereum)
      this.web3 = new Web3(window.ethereum)
    } else {
      this.web3 = this.createNewHttpProvider()
    }
  }

  public static get instance(): Web3Factory {
    if (!this._instance) {
      this._instance = new Web3Factory(window)
    }

    return this._instance
  }

  public getWeb3(): Web3 {
    return this.web3
  }

  private async getPermissionFromMetabask(ethereum: any): Promise<void> {
    try {
      await ethereum.enable()
    } catch (error) {}
  }

  private createNewHttpProvider(): Web3 {
    return new Web3(
      new Web3.providers.HttpProvider(
        'https://{your infura url}'
      )
    )
  }
}

export default Web3Factory

window.ts

import Web3 from 'web3'

declare global {
  interface Window {
    web3: Web3
    ethereum: any
  }
}

export default Window