eth-scan
eth-scan
is a library written in TypeScript, to help you fetch Ether or (ERC-20) token balances for multiple addresses in an efficient way. The library uses a smart contract to fetch the balances in a single call to a node. The contract is currently deployed at 0x86f25b64e1fe4c5162cdeed5245575d32ec549db on the Ethereum mainnet, Goerli, Kovan, Rinkeby and Ropsten.
It can use Web3.js, Ethers.js or regular HTTP as provider to get the balances. See Getting Started for more info.
Note: Even though eth_call
doesn't use any gas, the block gas limit still applies, and the maximum number of addresses you can fetch in a single call is limited. By default this library batches calls per 1000 addresses.
Getting started
The library is published on npm. To install it, use npm
or yarn
:
yarn add @mycrypto/eth-scan
or
npm install @mycrypto/eth-scan
Example
import { getEtherBalances } from 'eth-scan';
getEtherBalances('http://127.0.0.1:8545', [
'0x9a0decaffb07fb500ff7e5d253b16892dbec006a',
'0xeb65f72a2f5464157288ac15f1bb56c56e6be375',
'0x1b96c634f9e9fcfb76932e165984901701352ffd',
'0x740539b55ee5dc58efffb88fea44a9008f8daa6f',
'0x95d9e32dc03770699a6a5e5858165b174d500015'
]).then(console.log);
Results in:
{
'0x9a0decaffb07fb500ff7e5d253b16892dbec006a': BigNumber(1000000000000000000),
'0xeb65f72a2f5464157288ac15f1bb56c56e6be375': BigNumber(1000000000000000000),
'0x1b96c634f9e9fcfb76932e165984901701352ffd': BigNumber(1000000000000000000),
'0x740539b55ee5dc58efffb88fea44a9008f8daa6f': BigNumber(1000000000000000000),
'0x95d9e32dc03770699a6a5e5858165b174d500015': BigNumber(1000000000000000000)
}
API
getEtherBalances(provider, addresses, options)
Get Ether balances for addresses
.
-
provider
<Provider> - A Web3 instance, Ethers.js provider or JSONRPC endpoint.
-
addresses
<string[]> - An array of addresses as hexadecimal string.
-
options
<EthScanOptions> (optional) - The options to use.
-
Returns: <Promise<BalanceMap>> - A promise with an object with the addresses and the balances.
getTokenBalances(provider, addresses, token, options)
Get ERC-20 token balances from token
for addresses
. This does not check if the address specified is a token and will throw an error if it isn't.
-
provider
<Provider> - A Web3 instance, Ethers.js provider or JSONRPC endpoint.
-
addresses
<string[]> - An array of addresses as hexadecimal string.
-
token
<string> - The address of the ERC-20 token.
-
options
<EthScanOptions> (optional) - The options to use.
-
Returns: <Promise<BalanceMap>> - A promise with an object with the addresses and the balances.
getTokensBalance(provider, address, tokens, options)
Get ERC-20 token balances from tokens
for address
. If one of the token addresses specified is not a token, a balance of 0 will be used.
-
provider
<Provider> - A Web3 instance, Ethers.js provider or JSONRPC endpoint.
-
address
<string> - The address to get token balances for.
-
tokens
<string[]> - An array of ERC-20 token addresses.
-
options
<EthScanOptions> (optional) - The options to use.
-
Returns: <Promise<BalanceMap>> - A promise with an object with the addresses and the balances.
getTokensBalances(provider, addresses, tokens, options)
-
provider
<Provider> - A Web3 instance, Ethers.js provider or JSONRPC endpoint.
-
addresses
<string[]> - An array of addresses as hexadecimal string.
-
tokens
<string[]> - An array of ERC-20 token addresses.
-
options
<EthScanOptions> (optional) - The options to use.
-
Returns: <Promise<BalanceMap<BalanceMap>>> - A promise with an object with the addresses and the balances.
EthScanOptions
-
contractAddress
<string> (optional) - The address of the smart contract to use. Defaults to 0x86f25b64e1fe4c5162cdeed5245575d32ec549db.
-
batchSize
<number> (optional) - The size of the call batches. Defaults to 1000.
BalanceMap
A BalanceMap
is an object with an address as key and a BigNumber as value.
Providers
Currently, eth-scan
has support for three different providers:
- Ethers.js, by using an existing Ethers.js provider
- Web3, by using an instance of the
Web3
class - HTTP, by using a URL of a JSONRPC endpoint as string
Compatiblity
eth-scan
uses ES6+ functionality, which may not be supported on all platforms. If you need compatibility with older browsers or Node.js versions, you can use something like Babel.
There is an ES compatible version available, which should work with module bundlers like Webpack and Rollup.