Web3js Server-Side Connection Issues with Ganache – Troubleshooting Guide

ganachejavascriptnodejsweb3js

I need to create server in nodejs that will create transaction to blockchain and i have trouble to connect my nodejs app with ganache. Look at my code:

const Web3 = require('web3');
var web3 = new Web3.providers.HttpProvider('http://localhost:7545'); // ganache address
console.log(web3.eth.accounts); // should print 10 accounts but its error like eth is undefined

In my dependencies

"web3": "^0.20.2"

Using this code on client-side works, what am i missing?

Best Answer

This line is wrong:

var web3 = new Web3.providers.HttpProvider('http://localhost:7545');

You're instantiating a provider instead of instantiating Web3. It should be this:

var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:7545'));

Related Solutions

[Ethereum] How to load external JavaScript files into app.js – Truffle

A function cannot be called unless it was defined in the same file or one loaded before the attempt to call it.

A function cannot be called unless it is in the same or greater scope then the one trying to call it.

You declare function fn1 in first.js, and then in second you can just have fn1();

1.js :

function fn1 (){
    alert();
}

2.js :

fn1();

index.html :

<script type="text/javascript" src="1.js"></script>
<script type="text/javascript" src="2.js"></script>

It works fine :)

[Ethereum] Result of calling web3.version.getNetwork() from browser-side code is always undefined

Yes, your right it will return undefined. Because web3.version.getNetwork() is not a sync method and it will not return any value. In javascript, If function is not return any method it will init varible is undefined. Refer below code for ref:

web3.version.getNetwork(function(err, networkId){
            switch(networkId){
                case "1":
                    //TODO your logic...
                    break;
                default:
                    //If neteork id is not mattching...
            }
});

Best Answer

Related Solutions

[Ethereum] How to load external JavaScript files into app.js – Truffle

[Ethereum] Result of calling web3.version.getNetwork() from browser-side code is always undefined

Related Topic