如何使用 Web3 访问映射变量的值

Question

I have a variable of a mapping type that I want to access the value of from the front end:

mapping(address => uint) public etherBalanceOf;

I store the contract in a state

const test = new web3.eth.Contract(test.abi, test.networks[netId].address)
this.setState({test})

and make the web3 call as following:

if(this.state.test !== "undfined") {
  try {
    const depositBalance = await this.state.test.etherBalanceOf.call(this.state.account)
    console.log(depositBalance)
  } catch(e) {
    console.log("Error, checking balance", e)
  }
}

But, I get an error saying:

TypeError: Cannot read property 'call' of undefined

Answer 1

etherBalanceOf takes in an address as argument

Instead of

const depositBalance = await this.state.test.etherBalanceOf.call(this.state.account)

pass in an address to etherBalanceOf(address)

const depositBalance = await this.state.test.etherBalanceOf(this.state.account).call()