Provider not set or invalid in metamask

Question

I'm using metamask to connect to rinkeby network. I can see metamask injects web3 code just fine, still I get the Error: Provider not set or invalid. Here's the js script I wrote.

var Web3 = require('web3');
var web3 = new Web3();

if (typeof web3 !== 'undefined') {
    console.log("Using web3 detected from external source like Metamask");
    web3 = new Web3(web3.setProvider(web3.currentProvider));

} else {
    console.log("Using localhost");
    web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
}

var account = web3.eth.accounts[0];

console.log(account);

Here's the error I'm getting

I'm using webpack, web3 0.20.4. How do I solve this?

Answer 1

You actually shouldn't be setting a provider within a new Web3 instance if you already have the web3.currentProvider.

Replace:

web3 = new Web3(web3.setProvider(web3.currentProvider));

with:

web3 = new Web3(web3.currentProvider);

---

Also, do not create the web3 instance before checking for the browser version.

Replace the line:

var web3 = new Web3();

with:

var web3 = window.web3;