Displaying the adaptive errors in the contents on the front
When building complex decentralized applications (DAPP), it is not uncommon to face custom errors that cannot be attached to traditional error -handling mechanisms. In this article, we will look at how these customized errors are presented at the front at the Ethereum Web3.JS library.
Why do you show custom mistakes?
Custom errors are often the result of unexpected logic in your contract or in third parties integrations. By showing them in the front, you can:
- Improve the user experience : Users appreciate a clear indication that something went wrong.
- Improve Error Correction Tools : Developers can use these custom errors to identify and repair problems more effectively.
Prerequisites
Make sure before diving in, make sure you have:
- Basic understanding of stability and web3.js
The contract used for the * Ethereum block chain
Displaying the custom errors web3.js
In this example, we use web3.js' to display custom errors in the front. We create an event Emitter, which listens to the "Customerror" transactions sent by the agreement.
First, installweb3.jsand w3 -loggerlibraries:
Bash
NPM Install Web3 W3 Logger
`
Implementation of the Agreement
`Solidity
Pragman solidity 0.8,16;
Contract Test {
Event Customerror (Uint256 value);
UINT PUBLIC A;
Builder () Public {
Emit Customerror (10); // example error code
}
Function Test Function () External Pure Return (Bool) {
A = 5; // This should trigger a custom error
return the truth; // successful execution
}
}
`
Frontend implementation
`Javascript
Bring * W3 “Web3”;
Bring {events} “W3-logger”;
the front of the class {
Builder (W3instance) {
This.w3 = w3instance;
Const Eventmitter = New Events ();
Eventemitter.on (“Customerror”, (Errorvalu) => {
Console.error (custom error: $ {errorvalu});
// deal with custom error logic here
});
// take the contract
DeployContract (W3instance);
}
Async DeployContract (W3instance) {
Const contractionaddress = “0x …”; // replace with a contract address
Conscombabi = “…”; // replace with agreement abi
Const Web3 = New W3.Web3 (W3instance, Compa Chatracabi);
Wait web3.eth.deployContract (contractionaddress);
}
}
`
Driving the front
To complete this front application, you need to create a new firm contract and enable it. Then bring the “FrontendApp” class and call it to the builder.
`Javascript
Const w3instance = require (“web3”) (“http: // Localhost: 8545”);
Const FrontApp = New FrontApp (W3instance);
`
Custom error processing
In the ENAKK application you can handle custom errors in the trial block:
`Javascript
Try {
Const Result = Wait FrontApp.testfunction ();
Console.log (result);
} catch (error) {
Console.error (custom error: $ {error.message});
}
`
By showing the adaptive errors on the homepage, you can improve your application experience and make it easier to identify and fix developers.
conclusion
Displaying custom errors is a necessary step in the construction of strong decentralized applications. Using web3.js and to implement a custom error processing system, you can improve the usability and error correction features of the user interface application. This example shows how to introduce the contract with the Ethereum block chain and present customized errors in the front using web3.JS.