18

So I have a deployed contract with address0. I can easily interact with it using my index.html like so:

import contract_artifacts from '../../build/contracts/contract.json' var contract0 = contract(contract_artifacts);

Then I can call it's functions like so:

contract0.deployed().then(function(something){});

But I also have another previously deployed contract with address1. The contract is the same as the contract with the address0. I see only one way to work with the contract1:

var abiarray = [ here goes pretty big abi ]; contract1 = web3.eth.contract(abiarray).at(address1);

Is there another way to do it without including the whole abi of the contract? Because I already have it in contract_artifacts, I just don't know how to get it from there. Thank you.

Improve this question

4 Answers 4

Reset to default
20

I know the question is old, but I had some problems with this so I will share what helped me.

To import the ABI from a JSON file, you can use the following code (assuming you already have your web3 Object):

var fs = require('fs'); var jsonFile = "pathToYourJSONFile/project.json"; var parsed= JSON.parse(fs.readFileSync(jsonFile)); var abi = parsed.abi; var YourContract= new web3.eth.Contract(abi, 0x12345678912345678912345678912345678912);

You can read more about it here: https://web3js.readthedocs.io/en/1.0/web3-eth-contract.html

Update 01/2020: Since Typescript 2.9, reading JSON Files is supported directly. So if you try to get the ABI or Bytecode from within a Typescript Project (Angular, React, ...) simply go to your tsconfig.json and set: 

{ "compilerOptions": { "resolveJsonModule": true, "esModuleInterop": true } }

You can then use import ContractName from 'path/to/contract/ContractName.json' to import your Contracts and get the Abi with ContractName.abi.

Cheers

Improve this answer
2
  • 5
    I'm surprised this is one of the only few answers to this problem online.... most of the articles I read is asking you to type the ABI manually in js, which is really messy. Commented Jul 19, 2018 at 7:10
  • 1
    I'm getting an error: Error: Cannot find module '../../node_modules/file-system' - even though I absolutely have file system installed - both globally and locally in my project's folder... Strangely the error says its on line 210 of web3.min.js - which I wouldn't think is related to any of this. Thoughts? Commented Feb 19, 2019 at 15:59
7

I used the require function to import the JSON file.

import Web3 from 'web3'; const web3 = new Web3(window.web3.currentProvider); const { abi } = require('./smart_contract_after_compilation_step.json'); var smart_contract_interface = new web3.eth.Contract(abi, '0x5E54780072f1998FB85c3203D9697ef9E3F82DF0')
Improve this answer
3
  • Using "require" function from where? Commented May 20, 2021 at 21:10
  • In NodeJS/ExpressJS Commented May 22, 2021 at 18:33
  • This is the only solution shown here that solves my problem. Thanks! Commented Jun 29, 2021 at 23:33
3

In the frontend i just do this:

import MyContract fom './contracts/MyContract.json'; //truffle project dir web3 = new Web3(Web3.givenProvider); const myContractWeb3 = new web3.eth.contract(MyContract.abi, "0x00"); // and then call the function that I want to const functionThatIWantToUseFromSmartContract = async () =>{ const account = await window.ethereum.enable(); const accounts = account[0]; const gas = await myContractWeb3.methods.theFunction(args).estimateGas(); await myContractWeb3.methods.theFunction(args).send(); }
Improve this answer
0

Reading JSON Files is supported directly. In my Nodejs Express App I loaded the contract:

// Load Contract var fs = require('fs'); var jsonFile = "abis/abi.json"; var abi = JSON.parse(fs.readFileSync(jsonFile)); // Contract var contract = new web3.eth.Contract(abi, "0x068_your_address");
Improve this answer

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.