TypedContract

TypedContract - ethers.js Contract with type definitions inferred from the ABI.

npm install ethers-typed-contract
# or
yarn add ethers-typed-contract

import TypedContract from "ethers-typed-contract";

// Get the ABI
const ABI = <const>[
  {
    type: "function",
    name: "transfer",
    stateMutability: "nonpayable",
    inputs: [
      { name: "recipient", type: "address" },
      { name: "amount", type: "uint256" },
    ],
    outputs: [{ name: "", type: "bool" }],
  },
];

// Create a contract instance, providing the `ABI`
const token = new TypedContract(erc20Address, ABI);

// method name, arguments and return types are inferred from the `ABI`
await token.transfer("0x0000000000000000000000000000000000000123", 100);

await token.transfer(1, 2); // compile error: `1` is not assignable to address
await token.unknownMethod(123); // compile error: Property 'unknownMethod' does not exist

Known limitations

• Solidity structs are not yet supported. TODO

• Function and events parameters and return names are not preserved (issues and PRs are welcome if you know how to make a named tuple from a mapped object)

• Fixed-sized arrays must have max of 997 elements for the correct types to be generated

• It's impossible to use JSON ABI files because typescript does not allow importing JSON files as const. Typescript issue. To work this around:

  1. Rename your .json file to .ts

  2. Insert export default <const> at the beginning of the ABI file, so the abi looks like this:

     export default <const>[
       // ABI
     ];

TODO

• Support more data types:
  • all primitive types
  • struct
  • arrays
• Support for contract.interface
• Support for functions:
  • overloaded functions, e.g., contract['fn()'] and contract['fn(uint256)']
  • methods directly on a contract. E.g., contract.transfer
  • .functions, .callStatic, .estimateGas, and .populateTransaction buckets. E.g., contract.functions.transfer
• Support for events*:
  • filters
  • queryFilter, on, once, off, listeners, removeListener, removeAllListeners *

* queryFilter, on, once, off, listeners, removeListener, removeAllListeners have full type safety but I couldn't make them match the typechain typings.