Web3

Web3 specific functionality of the Moralis SDK.

Lets talk about Web3 integration!

Moralis comes with a set of plugins to help you focus on your development of your app and leave the rest to us.

Moralis SDK Web3 API

Enable

Similar to window.ethereum.enable() but returns a promise that resolves to a Web3 instance. Use this when you need a fully functional Web3 instance, like for making contract calls.

const web3 = await Moralis.Web3.enable();
const contract = new web3.eth.Contract(contractAbi, contractAddress);

If you just need to access web3.utils without web3 connectivity. Use the following.

const web3 = new Moralis.Web3();
const amountInEth = web3.utils.fromWei(amountInWei, 'ether');

Just beware that calls like web3.eth.getAccounts() will not work. You can re-assign the variable using Moralis.Web3.enable() later if you need full Web3 connectivity.

See the Web3.js docs https://web3js.readthedocs.io/ for more info on the Web3 object.

Events

There are wrappers for the standard Web3 change events.

  • onConnect

  • onDisconnect

  • onChainChanged

  • onAccountsChanged

const unsubscribe = Moralis.Web3.onAccountsChanged(function(accounts) {
console.log(account);
});
// ["0x0f7056a5778b15ebd522f39ab9782abf3ee37f08"]

Linking

Link (unlink) an address to the current user.

  • link(address)

  • unlink(address)

The user may have multiple addresses they wish to associate with their profile. This can be done with the link function after the user has been authenticated.

Moralis.Web3.onAccountsChanged(async function (accounts) {
const confirmed = confirm('Link this address to your account?');
if (confirmed) {
await Moralis.Web3.link(accounts[0]);
alert('Address added!');
}
});

The unlink function removes the given address from the user's profile.

await Moralis.Web3.unlink(address);

Also see the Users section.

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