Methods to Name a Good Contract Operate from JavaScript

Utilizing the enterprise-grade EVM API from Moralis, builders can simply name a sensible contract operate from JavaScript. Merely set up Moralis’ SDK and name the ”runContractFunction” endpoint! Moreover, by defining particular parameters within the code snippet beneath, together with the contract deal with, operate title, ABI, and so on., you may run any EVM ”read-only” contract operate with just a few strains of code:

const response = await Moralis.EvmApi.utils.runContractFunction({
    deal with,
    functionName,
    abi, 
  });

In order for you extra data on how this works, examine the documentation web page to run a contract operate or comply with alongside on this tutorial as we apply this in apply! That stated, irrespective of which path you determine to comply with, that you must have a Moralis account. So, create one without spending a dime now and unlock the ability of blockchain!

Overview

Good contracts are on the core of blockchain growth and are important parts of the Web3 ecosystem. Within the case of Ethereum, sensible contracts include two components, certainly one of which is wise contract features. Such a operate is a chunk of code used a number of instances to carry out given duties. Consequently, in Web3 growth, it’s extremely useful for a developer to know the right way to run Web3 contract strategies. If you wish to learn the way to take action, be a part of us on this tutorial as we present you the right way to name a sensible contract operate from JavaScript utilizing Moralis!

Earlier than we present you the right way to name a sensible contract operate from JavaScript, the article will briefly cowl the intricacies of each contracts and features. So, if you’re already acquainted with these ideas, be at liberty to skip straight into the central a part of the tutorial.

To name sensible contract features seamlessly, we might be utilizing Moralis’ Ethereum Web3 API. Nevertheless, that is solely one of many distinguished blockchain growth instruments supplied by Moralis. As such, if you’re really critical about changing into a blockchain developer, you must discover a few of Moralis’ different interfaces. An instance is the Streams API, enabling you to rapidly arrange Web3 webhooks to stream on-chain information straight into the backend of Web3 initiatives!

So, if you wish to entry these instruments and totally leverage the ability of blockchain expertise, join with Moralis now solely without spending a dime!

Exploring Contracts and Features – Methods to Name Good Contract Operate from JavaScript

Earlier than exploring the right way to name a sensible contract operate with JavaScript, the article will briefly dive into the intricacies of contracts and features. If you’re already acquainted with these two ideas, be at liberty to skip straight into the ”Methods to Name Good Contract Operate from JavaScript” tutorial. In any other case, be a part of us within the following sections, the place we begin by answering the query, ”what are sensible contracts?”.

What are Good Contracts?

Good contracts – additionally typically known as ”Web3 contracts” – are on the spine of the Web3 ecosystem and are basically codified agreements between two or extra events over the web. Consequently, sensible contracts have the identical elementary functions as conventional contracts. Nevertheless, there’s a essential distinction between sensible contracts and conventional ones that’s fairly vital to pay attention to. The code on the blockchain regulates the ”phrases and situations” relatively than a third-party actor.

developer constructing smart contract and calling it with JavaScript

To slender the scope barely, allow us to focus extra particularly on Ethereum sensible contracts, as that is the most well-liked community for blockchain growth. These sensible contracts are applications working on the Ethereum blockchain. Moreover, they include two core parts: code and information. The code is a set of features, and the info is the contract’s state.

A typical metaphor for describing the performance of a sensible contract is a digital merchandising machine. Like conventional merchandising machines, sensible contracts produce assured outputs primarily based on given inputs. Accordingly, you may present contracts with cryptocurrency, and so they run code in return.

Nonetheless, that briefly covers sensible contracts. For a extra profound breakdown, take a look at our article on Web3 contracts! Now, let’s get extra particular and discover certainly one of their core parts: sensible contract features!

What are Good Contract Features?

As we briefly talked about within the preliminary part, features are certainly one of two core parts of Ethereum sensible contracts. So, what precisely are sensible contract features? A wise contract operate is a chunk of reusable code that may be known as from exterior or inside a specific sensible contract that accomplishes a particular process. Creating features offers a number of advantages, resembling eliminating the necessity to write code a number of instances and lowering the possibility of errors occurring.

two workers exchanging contract by calling a smart contract function from JavaScript code

Moreover, there are two forms of sensible contract features:

Features that generate on-chain transactions.
Features which might be ”read-only” and, subsequently, don’t lead to blockchain transactions.

On this tutorial, we’ll deal with the previous. Particularly, within the subsequent part, we’ll present you the right way to use Moralis to name a ”read-only” sensible contract operate from JavaScript. If this sounds thrilling, keep caught in as we cowl the method from begin to end!

Methods to Name Good Contract Operate from JavaScript

The next tutorial sections illustrate how one can name a sensible contract operate from JavaScript. To make this as accessible as potential as you comply with our lead, we’ll make the most of Moralis’ EVM API and the ”runContractFunction” endpoint. By this endpoint, you may name any ”read-only” sensible contract operate from JavaScript with only some strains of code!

To show how this works, we’ll present you the right way to name the ”getPrice()” operate of the “Cool Cats” NFT contract. Calling this operate returns the minting worth of the tokens, which you should use as you see slot in your growth endeavors. Here’s a fast overview of the elements we cowl on this article:

Set Up a NodeJS Mission
Add the Code to the ”index.js” File
Run the Program

By protecting the sections above, you’ll be taught not solely the right way to name ”getPrice()” however any ”read-only” sensible contract operate. So, if this sounds thrilling, be a part of us on this tutorial as we kick issues off by exhibiting you the right way to arrange a NodeJS venture!

Nevertheless, maybe you like watching YouTube movies to teach your self. If that’s the case, you may also take a look at the Moralis YouTube clip beneath. On this video, you could find a complete breakdown of your complete course of, together with extra examples of different sensible contract operate calls:

Set Up a NodeJS Mission

On this preliminary part of the tutorial on the right way to name a sensible contract operate from JavaScript, we’ll present you the right way to arrange a NodeJS venture. As such, to start with, you probably have not already, be sure that to put in the newest model of NodeJS. You’ll be able to obtain and set up it utilizing the next hyperlink: “https://nodejs.org/en/”.

From there, open your built-in growth surroundings (IDE) and create a brand new venture folder. We’re utilizing Visible Studio Code (VSC) all through the article. As such, for those who go for one other surroundings, observe that there would possibly often be slight variations within the course of. Nonetheless, after getting opened your IDE, go forward and launch a brand new terminal. If you’re utilizing VSC, click on on the ”Terminal” tab on the prime after which hit ”New Terminal”:

From there, you may initialize a brand new NodeJS venture by working the command beneath within the venture’s root folder:

npm init -y

With the venture initialized, you additionally want to put in the required dependencies. To take action, run this command within the terminal:

npm i moralis dotenv

That covers the preliminary setup strategy of the NodeJS venture. Nevertheless, from right here, you additionally want so as to add three new information ”.env”, ”abi.json”, and ”index.js”. As such, within the following sub-section, we’ll present you the right way to create them and take a more in-depth take a look at what content material you will need to add to every.

Add ”.env”, abi.json”, and ”index.js”

The primary file that you must create is ”.env”, which might be used to soundly retailer your Web3 API key. As such, open the file and create a brand new ”MORALIS_KEY” surroundings variable. It ought to look one thing like this:

MORALIS_KEY = “JnJnO…”

Nevertheless, as you might need concluded already, that you must exchange ”JnJnO…” together with your precise key. To get the important thing, that you must have an lively Moralis account. So both log in or join with Moralis without spending a dime proper now. From there, log in to the admin panel, go to the ”Web3 APIs” tab, copy the important thing, and enter it into the ”.env” file:

Now that you’ve added your Moralis API key, the following step is to create the ”abi.json” file. For this file, it would be best to add the ABI of the contract you have an interest in. To get the contract ABI, we’ll use the Etherscan blockchain explorer. Particularly, we’ll use the Cool Cats NFT contract to show how this works.

Nonetheless, open Etherscan and navigate to the contract you have an interest in. In our case, it seems one thing like this:

etherscan landing page showing cool cats smart contract

From there, scroll down and click on on the ”Contract” tab:

You’ll be able to then scroll down even additional, and you must discover the contract ABI virtually on the backside:

Copy this code and enter it into the ”abi.json” file. It ought to now look one thing like this:

abi json file with code structure to call smart contract function with JS code

Lastly, the final file that you must add is ”index.js”. This would be the file to which we add the logic used to name a sensible contract operate from JavaScript. Consequently, this ”index.js” requires additional consideration, which is why we dedicate the next part to breaking down the code!

Add the Code to the ”index.js” File

Now that you’ve arrange the NodeJS venture and created the required information, it’s time to add the code used to name a sensible contract operate from JavaScript. So, to start with, open ”index.js” and add the next code snippet on the prime of the file:

const Moralis = require("moralis").default;
require("dotenv").config();
const ABI = require("./abi.json");

The above code imports Moralis, offers entry to the contents of the ”.env” file, and shops the contract ABI within the ”ABI” variable. From there, that you must initialize Moralis and go the Web3 API key you specified earlier as a parameter. To take action, add the next code beneath the ”ABI” variable:

Moralis.begin({
  apiKey: course of.env.MORALIS_KEY
})

Subsequent, with Moralis initialized, create a brand new asynchronous operate. This operate will use Moralis’ EVM API to name the ”runContractFunction” endpoint with just a few parameters. On this case, since we wish to name the ”getPrice()” operate, you solely want so as to add the ”deal with”, ”functionName”, and ”abi” as parameters:

.then(async()=>{

const response = await Moralis.EvmApi.utils.runContractFunction({
  deal with:"0x1A92f7381B9F03921564a437210bB9396471050C",
  functionName:"getPrice",
  abi: ABI
})

Lastly, to prime issues off, we console-log the response by including the next code on the backside of the ”index.js” file:

console.log(response.uncooked)

All in all, your file ought to now look one thing like this:

const Moralis = require("moralis").default;
require("dotenv").config();
const ABI = require("./abi.json"); 

Moralis.begin({
  apiKey: course of.env.MORALIS_KEY
}).then(async()=>{

  const response = await Moralis.EvmApi.utils.runContractFunction({
    deal with:"0x1A92f7381B9F03921564a437210bB9396471050C",
    functionName:"getPrice",
    abi: ABI
  })
  
  
  console.log(response.uncooked) 
})

So, by working the ”index.js” file, this system ought to return the mint worth of the Cool Cats NFTs. Nonetheless, allow us to briefly present you the right way to run this system and evaluate the ends in the following part!

Run the Program

Lastly, now that you’ve added the code used to name a sensible contract operate, all that continues to be is working this system. To take action, open a brand new terminal and easily run the next command:

node index.js

This executes the code, and you must obtain a response just like the one proven beneath:

result page from using JavaScript and calling the smart contract function

The response is ”20000000000000000”, which is the quantity ”2” adopted by sixteen zeros. As such, that is the mint worth with out contemplating the decimals. The precise worth is 0.2 ETH.

Congratulations! That’s it for this tutorial! In case you have adopted alongside this far, you now know the right way to name a sensible contract operate from JavaScript. What’s extra, despite the fact that we confirmed you the right way to name the ”getPrice()” operate, specifically, you may apply the identical elementary ideas to name different ”read-only” features of any EVM-based contract!

If you wish to take a look at what different sensible contract features can be found, you may carefully look at the ”abi.json” file or browse Etherscan. For Etherscan, you may click on on the ”Contract” tab after which hit ”Learn Contract” to search out all features obtainable. As an example, here’s what it seems like for the Cool Cats contract:

What’s extra, if you would like additional data on the right way to name a sensible contract operate with JavaScript, take a look at the EVM API documentation or the documentation web page to run a contract operate.

Abstract – Methods to Name Good Contract Operate From JavaScript

On this article, we taught you the right way to name a sensible contract operate from JavaScript utilizing Moralis. Extra particularly, we used the ”runContractFunction” endpoint to name the ”getPrice()” operate of the Cool Cats contract. Consequently, you probably have adopted alongside this far, you should use the identical elementary ideas to name any sensible contract operate sooner or later!

When you discovered this tutorial informative, be sure that to take a look at extra Moralis-based content material right here on the Web3 weblog. As an example, discover the most effective Ethereum API in 2023 or be taught the variations between ethers.js vs Web3 streams!

Nonetheless, it doesn’t matter what blockchain endeavor you embark on sooner or later, join with Moralis now, as this Web3 supplier facilitates a extra seamless developer expertise for everybody!

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