@truffle/abi-utils

Utilities for working with ABIs

Usage no npm install needed!

<script type="module">
  import truffleAbiUtils from 'https://cdn.skypack.dev/@truffle/abi-utils';
</script>

README

@truffle/abi-utils

Contains a few utilities for dealing with ABIs.

Contents

This package contains a few different components:

Normalize ABIs

// handle function entries omitting "type" from JSON
const isFunctionEntry = entry.type === "function" || !("type" in entry);

// handle:        v--- new way                           v--- old way     v--- default
const isPayable = entry.stateMutability === "payable" || entry.payable || false;

// handle "outputs" possibly being undefined
const outputs = entry.outputs || [];

^ Have you ever had to do this sort of thing? :scream:

Solidity's official JSON ABI specification is rather permissive, since it remains backwards compatible with older versions of the language and because it permits omitting fields with default values. This can get annoying if you're programmatically processing ABIs.

:information_source: This package provides a normalize function to purge these kinds of inconsistencies.

const { normalize } = require("@truffle/abi-utils");

import { normalize } from "@truffle/abi-utils";

Specifically, this normalizes by:

  • Ensuring every ABI entry has a type field, since it's optional for type: "function"
  • Populating default value [] for function outputs field
  • Removing all instances of the legacy payable and constant fields
  • Replacing those two fields with the newer stateMutability field

To use, provide the ABI as a JavaScript array, as the sole argument to the function:

// accepts ABIs from Solidity versions back to 0.4.12 or earlier!
const abi = normalize([{"type": "constructor"/*, ...*/}/*, ...*/);

// don't even worry about it
const isFunctionEntry = entry.type === "function";
const isPayable = entry.stateMutability === "payable";

TypeScript types

This package exports the following types for normalized ABIs.

  • Abi, to represent the full ABI array
  • Entry, to represent items in ABI arrays
  • FunctionEntry, to represent named functions
  • ConstructorEntry, to represent constructors
  • FallbackEntry, to represent old or new fallback functions
  • ReceiveEntry, to represent receive functions
  • Parameter, to represent parameters defined in entry inputs or outputs
  • EventParameter, to represent event parameters

To use these, you should first call normalize, described above.

import * as Abi from "@truffle/abi-utils";

const abi: Abi.Abi = [{"type": "constructor"/*, ...*/}/*, ...*/];
const parameter: Abi.Parameter = {"type": "tuple[]", "components": [/*...*/]};
// etc.

Arbitrary random ABIs

Do you need to test all the different kinds of ABIs, including testing your support for the various quirks across different Solidity versions? :flushed:

You can use this package for generating all sorts of random ABIs, random ABI events, random ABI parameter values, etc.

This package provides fast-check arbitraries for property-based testing methodologies. If you're not familiar with fast-check or property-based testing, please see the link above for more information.

import * as fc from "fast-check";
import { Arbitrary } from "@truffle/abi-utils";

// generate 10 random ABIs
const randomAbis = fc.sample(Arbitrary.Abi(), 10);

See this package's internal tests for normalize for example usage in automated tests.