检测MetaMask以太坊提供商，或任何注入window.ethereum的提供商。

node.js中使用 

import detectEthereumProvider from '@metamask/detect-provider'

const provider =  detectEthereumProvider();

if (provider) {

  console.log('Ethereum successfully detected!')

} else {

  // if the provider is not detected, detectEthereumProvider resolves to null

  console.error('Please install MetaMask!')

}

使用之前需要npm install @metamask/detect-provider 

html使用