@metamask/abi-utils
Lightweight utilities for encoding and decoding Solidity ABI.
yarn add @metamask/abi-utils
or
npm install @metamask/abi-utils
You can encode multiple values using encode
.
import { encode } from '@metamask/abi-utils';
import { bytesToHex } from '@metamask/utils';
const encoded = encode(['uint256', 'string'], [42, 'Hello, world!']);
// `abi-utils` returns a `Uint8Array`, so you can convert it to a hex string
// using `bytesToHex`.
console.log(bytesToHex(encoded));
// 0x000000000000000000000000000000000000000000000000000000000000002a
// 0000000000000000000000000000000000000000000000000000000000000040
// 000000000000000000000000000000000000000000000000000000000000000d
// 48656c6c6f2c20776f726c642100000000000000000000000000000000000000
Alternatively, you can encode a single value using encodeSingle
.
import { encodeSingle } from '@metamask/abi-utils';
const encoded = encodeSingle('uint256', 42);
// `abi-utils` returns a `Uint8Array`, so you can convert it to a hex string
// using `bytesToHex`.
console.log(bytesToHex(encoded));
// 0x000000000000000000000000000000000000000000000000000000000000002a
Encoding packed values, using the non-standard packed mode, is also supported.
This behaves the same as abi.encodePacked
in Solidity.
import { encodePacked } from '@metamask/abi-utils';
const encoded = encodePacked(['uint256', 'string'], [42, 'Hello, world!']);
// `abi-utils` returns a `Uint8Array`, so you can convert it to a hex string
// using `bytesToHex`.
console.log(bytesToHex(encoded));
// 0x000000000000000000000000000000000000000000000000000000000000002a48656c6c6f2c20776f726c6421
You can decode multiple values using decode
.
import { decode } from '@metamask/abi-utils';
const decoded = decode(
['uint256', 'string'],
'0x000000000000000000000000000000000000000000000000000000000000002a' +
'0000000000000000000000000000000000000000000000000000000000000040' +
'000000000000000000000000000000000000000000000000000000000000000d' +
'48656c6c6f2c20776f726c642100000000000000000000000000000000000000',
);
console.log(decoded); // [ 42n, 'Hello, world!' ]
Alternatively, you can decode a single value using decodeSingle
.
import { decodeSingle } from '@metamask/abi-utils';
const decoded = decodeSingle(
'uint256',
'0x000000000000000000000000000000000000000000000000000000000000002a',
);
console.log(decoded); // 42n
By default, encode
and decode
will not perform strict type checking. This
is because TypeScript does not narrow the type of the types
array being
passed to the functions.
If you want to perform strict type checking, you can assert the type of the
array as const
using the as const
assertion.
import { encode } from '@metamask/abi-utils';
// This can be inlined in the function call too.
const types = ['uint256', 'string'] as const;
// Works!
encode(types, [42, 'Hello, world!']);
// Type 'number' is not assignable to type 'string'.
encode(types, [42, 1337]);
This does not support all ABI types, like tuples and nested arrays, because
support for recursive types in TypeScript is limited. In those cases, the input
or output type will be unknown
.
The full API documentation for the latest published version of this library is available here.
nvm use
will automatically choose the right node version for you.yarn install
to install dependencies and run any required post-install scriptsRun yarn test
to run the tests once. To run tests on file changes, run yarn test:watch
.
Run yarn lint
to run the linter, or run yarn lint:fix
to run the linter and fix any automatically fixable issues.
The project follows the same release process as the other libraries in the MetaMask organization. The GitHub Actions action-create-release-pr
and action-publish-release
are used to automate the release process; see those repositories for more information about how they work.
1.x
for a v1
backport release).v1.0.2
release, you'd want to ensure there was a 1.x
branch that was set to the v1.0.1
tag.workflow_dispatch
event manually for the Create Release Pull Request
action to create the release PR.action-create-release-pr
workflow to create the release PR.yarn auto-changelog validate --rc
to check that the changelog is correctly formatted.action-publish-release
workflow to tag the final release commit and publish the release on GitHub.publish-release
GitHub Action workflow to finish. This should trigger a second job (publish-npm
), which will wait for a run approval by the npm publishers
team.publish-npm
job (or ask somebody on the npm publishers team to approve it for you).publish-npm
job has finished, check npm to verify that it has been published.