const mergeMiddleware = require('json-rpc-engine/src/mergeMiddleware')
const createScaffoldMiddleware = require('json-rpc-engine/src/createScaffoldMiddleware')
const createAsyncMiddleware = require('json-rpc-engine/src/createAsyncMiddleware')
const createWalletSubprovider = require('eth-json-rpc-middleware/wallet')
module.exports = createMetamaskMiddleware
function createMetamaskMiddleware ({
version,
getAccounts,
processTransaction,
processEthSignMessage,
processTypedMessage,
processPersonalMessage,
getPendingNonce,
}) {
const metamaskMiddleware = mergeMiddleware([
createScaffoldMiddleware({
// staticSubprovider
eth_syncing: false,
web3_clientVersion: `MetaMask/v${version}`,
}),
createWalletSubprovider({
getAccounts,
processTransaction,
processEthSignMessage,
processTypedMessage,
processPersonalMessage,
}),
createPendingNonceMiddleware({ getPendingNonce }),
])
return metamaskMiddleware
}
function createPendingNonceMiddleware ({ getPendingNonce }) {
return createAsyncMiddleware(async (req, res, next) => {
if (req.method !== 'eth_getTransactionCount') return next()
const address = req.params[0]
const blockRef = req.params[1]
if (blockRef !== 'pending') return next()
req.result = await getPendingNonce(address)
})
}