ethers-tools-nestjs

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Description

A lightweight NestJS wrapper around ethers-tools.
This package provides convenient integration of ethers-tools into NestJS applications using standard Nest patterns like decorators and modules. Compatible with TypeScript and pure JavaScript.
JSDoc is provided.

Installation

First, you will need ethers v6 and ethers-tools:

npm i ethers
npm i ethers-tools
npm i ethers-tools-nestjs

or

yarn add ethers
yarn add ethers-tools
yarn add ethers-tools-nestjs

or

pnpm add ethers
pnpm add ethers-tools
pnpm add ethers-tools-nestjs

---

✨ Features

✅ Validators

@IsEthAddress

@Exclude()
export class GetCoinInfoQuery {
  @Expose()
  @IsOptional()
  @IsEthAddress({ message: 'Invalid user address' })
  userAddress?: string;
}

🛠 Contract & MulticallUnit Factories

The ethers-tools-nestjs package provides built-in support for creating contract instances and MulticallUnit builders dynamically within a NestJS application.

📦 Contract Factory

You can register a contract factory using createContractFactoryProvider:

import { Module } from '@nestjs/common';
import { createContractFactoryProvider } from 'ethers-tools-nestjs';
import { Erc20Contract } from './erc20.contract';
import { Erc20Abi } from './abis';

const erc20factory = createContractFactoryProvider(Erc20Contract, {
  abi: Erc20Abi,
});

@Module({
  providers: [erc20factory],
  exports: [erc20factory],
})
export class ContractsModule {}

constructor(
  @InjectContractFactory(Erc20Contract)
  private readonly token: ContractFactory<Erc20Contract>,
) {}

🤖 Auto Contract Factory

You can register a contract factory without a manual contract creation using createAutoContractFactoryProvider:

import { Module } from '@nestjs/common';
import {
  createAutoContractFactoryProvider,
  createMulticallFactoryProvider,
} from 'ethers-tools-nestjs';
import { Erc721Abi } from '@/contracts/abis';
import { NftService } from './nft.service';

const multicallFactoryProvider = createMulticallFactoryProvider(
  NftService.name,
);
const autoNftFactoryProvider = createAutoContractFactoryProvider(
  NftService.name,
  Erc721Abi,
);

@Module({
  providers: [multicallFactoryProvider, autoNftFactoryProvider, NftService],
  exports: [NftService],
})
export class NftModule {}

constructor(
  @InjectAutoContractFactory(NftService.name)
  private readonly nft: AutoContractFactory,
) {}

⚡ MulticallUnit Factory

The MulticallUnitFactory allows you to batch multiple calls:

import { Module } from '@nestjs/common';
import { createMulticallFactoryProvider } from 'ethers-tools-nestjs';
import { ContractsModule } from '@/contracts';
import { TokenService } from './token.service';

const multicallFactoryProvider = createMulticallFactoryProvider(
  TokenService.name,
);

@Module({
  imports: [ContractsModule],
  providers: [multicallFactoryProvider, TokenService],
  exports: [TokenService],
})
export class TokenModule {}

constructor(
  @InjectMulticallFactory(TokenService.name)
  private readonly multicall: MulticallFactory,
) {}

👀 Example:

import { Injectable } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { InjectPinoLogger, PinoLogger } from 'nestjs-pino';
import { JsonRpcProvider } from 'ethers';
import { Chain } from 'ethers-tools';
import {
  ContractFactory,
  MulticallFactory,
  InjectContractFactory,
  InjectMulticallFactory,
} from 'ethers-tools-nestjs';
import { Erc20Contract } from '@/contracts';
import { TokenInfo } from '@/entities/token';

@Injectable()
export class TokenService {
  constructor(
    private readonly config: ConfigService,
    @InjectPinoLogger(TokenService.name)
    private readonly logger: PinoLogger,
    @InjectContractFactory(Erc20Contract)
    private readonly token: ContractFactory<Erc20Contract>,
    @InjectMulticallFactory(TokenService.name)
    private readonly multicall: MulticallFactory,
  ) {}

  public async getTokenInfo(
    chain: Chain,
    tokenAddress: string,
    userAddress?: string,
  ): Promise<TokenInfo> {
    const driver: JsonRpcProvider = this.config.getOrThrow(
      `providers[${chain}]`,
    );
    const multicall = this.multicall.create({
      driver,
    });
    const contract = this.token.create({
      address: tokenAddress,
      driver,
    });
    multicall.addBatch([
      { call: contract.getNameCall() },
      { call: contract.getSymbolCall() },
      { call: contract.getTotalSupplyCall() },
      { call: contract.getDecimalsCall() },
    ]);
    if (userAddress) multicall.add(contract.getBalancesCall(userAddress));

    await multicall.run();
    const [name, symbol, totalSupply, decimals, balances] =
      multicall.getAllOrThrow<
        [string, string, bigint, bigint, bigint | undefined]
      >();

    return {
      name,
      symbol,
      totalSupply: totalSupply.toString(),
      decimals: Number(decimals),
      balances: balances?.toString(),
    };
  }
}