I have encountered a problem with the web3js 1.0 library.

I have a simple function that is getting a balance from a smart contract:

async balance() {
  return await this.Marketplace.balances(this.storeOwner);

I have another function inside my angular component where I display the balance to the user:

async getBalance() {
  const balance = await this.smartContract.balance();
  this.balance = this.smartContract.web3.utils.fromWei(balance, 'ether');

When calling the web3.utils.fromWei() function I get this error:

Error: Uncaught (in promise): Error: Please pass numbers as strings or BigNumber objects to avoid precision errors.

but the console log shows me, that the balance is a BigNumber object:

BigNumber {s: 1, e: 0, c: Array(1)}

I am using version 1.0.0-beta.36. Why do I get the error?

  • did you try to convert balance to string? Like this: web3.utils.fromWei(''+balance, 'ether') – abed Dec 30 '18 at 23:40
  • Check if you have a dependency on a different version of web3 like v0.20. – Ismael Dec 31 '18 at 5:36
  • 1
    web3.js v0.x relies on BigNumber. web3.js v1.x relies on BN. To be on the safe side, use balance.toFixed(), which will guarantee a correct type (string) and a correct format (explicit decimal). – goodvibration Dec 31 '18 at 8:10
  • balance.toString() works. – Daniel Gretzke Jan 1 at 1:24
  • @goodvibration you're right. I use truffle to create the smart contract instance, which uses 0.x and pass the result to my web3 1.0 method. that's why it doesn't work – Daniel Gretzke Jan 1 at 1:26

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.