Example provider enablement code for EIP-1102

provider-enable.js

window.addEventListener('load', async () => {
    // Modern dapp browsers...
    if (window.ethereum) {
        window.web3 = new Web3(ethereum);
        try {
            // Request account access if needed
            await ethereum.enable();
            // Acccounts now exposed
            web3.eth.sendTransaction({/* ... */});
        } catch (error) {
            // User denied account access...
        }
    }
    // Legacy dapp browsers...
    else if (window.web3) {
        window.web3 = new Web3(web3.currentProvider);
        // Acccounts always exposed
        web3.eth.sendTransaction({/* ... */});
    }
    // Non-dapp browsers...
    else {
        console.log('Non-Ethereum browser detected. You should consider trying MetaMask!');
    }
});

Hi

Broken code. How could line 4 work? ethereum is undefined.

Is there a way to check if the user already enabled the dapp and skip calling await ethereum.enable(); again?

@Ramarti That would be possible with implementation of the feature request in Issue #6022.

@levino the code works because ethereum is on the global window object. window.ethereum is the same as a global ethereum variable because in a browser, window is the global context. Same reason window.document is accessible by only referencing document. Open your browser console & give it a try.

Hi guys!
I was wondering.

What the difference / recommended way is between this:

// Modern dapp browsers...
if (window.ethereum) {
  window.web3 = new Web3(ethereum);
  try {
    // Request account access if needed
    await ethereum.enable();
    // Acccounts now exposed
  }

and this:

// from eip1102
if (window.ethereum) {
  try {
    // Request account access if needed
    const accounts = await ethereum.send('eth_requestAccounts');
    // Accounts now exposed, use them   
  }

undefined etherum fixed

   if (window.ethereum) {
      window.web3 = new Web3(window.ethereum);
      try {
        // Request account access if needed
        await window.ethereum.enable();
        // Acccounts now exposed
        this.web3.eth.sendTransaction({/* ... */ });
      } catch (error) {
        // User denied account access...
      }
    }
    // Legacy dapp browsers...
    else if (window.web3) {
      window.web3 = new Web3(this.web3.currentProvider);
      // Acccounts always exposed
      this.web3.eth.sendTransaction({/* ... */ });
    }
    // Non-dapp browsers...
    else {
      console.log('Non-Ethereum browser detected. You should consider trying MetaMask!');
    }

Did it work your work I did what I was supposed to?