The Ethereum provider object injected by MetaMask into various environments. Contains a lot of implementation details specific to MetaMask, and is probably not suitable for out-of-the-box use with other wallets.
The BaseProvider
implements the Ethereum JavaScript provider specification (EIP-1193), but must be modified by a sub-class in order to function.
StreamProvider
is such a sub-class, which synchronizes its state and marshals JSON-RPC messages via a duplex stream.
MetamaskInpageProvider
further extends StreamProvider
to support legacy provider interfaces in addition to EIP-1193, and is used to instantiate the object injected by MetaMask into web pages as window.ethereum
.
import { initializeProvider } from '@metamask/providers';
// Create a stream to a remote provider:
const metamaskStream = new LocalMessageDuplexStream({
name: 'inpage',
target: 'contentscript',
});
// this will initialize the provider and set it as window.ethereum
initializeProvider({
connectionStream: metamaskStream,
});
const { ethereum } = window;
Types are exposed at index.d.ts
.
They require Node.js EventEmitter
and Duplex
stream types, which you can grab from e.g. @types/node
.
The Provider object should not be mutated by consumers under any circumstances. The maintainers of this package will neither fix nor take responsbility for bugs caused by third parties mutating the provider object.
nvm use
will automatically choose the right node version for you.yarn setup
to install dependencies and run any requried post-install scripts
yarn
/ yarn install
command directly. Use yarn setup
instead. The normal install command will skip required post-install scripts, leaving your development environment in an invalid state.Run 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:
main
1.x
)yarn version --minor --no-git-tag-version
)main
or 1.x
)