A tiny utility for detecting the MetaMask Ethereum provider, or any EIP 1193-compliant provider.
npm install @metamask/detect-providerA tiny utility for detecting the MetaMask Ethereum provider, or any provider injected at window.ethereum.
It has 0 dependencies and works out of the box in any modern browser, for synchronously and asynchronously injected providers.
Keep in mind that the providers detected by this package may or may not support the Ethereum JavaScript Provider API.
Please consult the MetaMask documentation to learn how to use our provider.
``javascript
import detectEthereumProvider from '@metamask/detect-provider'
const provider = await detectEthereumProvider()
if (provider) {
console.log('Ethereum successfully detected!')
// From now on, this should always be true:
// provider === window.ethereum
// Access the decentralized web!
// Legacy providers may only have ethereum.sendAsync
const chainId = await provider.request({
method: 'eth_chainId'
})
} else {
// if the provider is not detected, detectEthereumProvider resolves to null
console.error('Please install MetaMask!', error)
}
`
`html`
The exported function takes an optional options object.
If invalid options are provided, an error will be thrown.
All options have default values.
#### options.mustBeMetaMask
Type: boolean
Default: false
Whether window.ethereum.isMetaMask === true is required for the returned Promise to resolve.
#### options.silent
Type: boolean
Default: false
Whether error messages should be logged to the console.
Does not affect errors thrown due to invalid options.
#### options.timeout
Type: number
Default: 3000
How many milliseconds to wait for asynchronously injected providers.
Providers can be either synchronously or asynchronously injected:
- _Synchronously_ injected providers will be available by the time website code starts executing.
- _Asynchronously_ injected providers may not become available until later in the page lifecycle.
The MetaMask _extension_ provider is synchronously injected, while the MetaMask _mobile_ provider is asynchronously injected.
To notify sites of asynchronous injection, MetaMask dispatches the ethereum#initialized event on window immediately after the provider has been set as window.ethereum.
This package relies on that event to detect asynchronous injection.
The detected provider object returned by this package will strictly equal (===) window.ethereum for the entire page lifecycle, unless window.ethereum is overwritten.window.ethereum
In general, consumers should never overwrite or attempt to modify the provider object.
If, as a dapp developer, you notice that the provider returned by this package does not strictly equal window.ethereum, something is wrong.window.ethereum`, you should ask the user to ensure that they only have a single provider-injecting wallet enabled at any one time.
This may happen, for example, if the user has multiple wallets installed.
After confirming that your code and dependencies are not modifying or overwriting