Introduction
When working with MetaMask APIs, you might encounter this warning: “Property ’ethereum’ does not exist on type ‘Window & typeof globalThis’.ts(2339)” when accessing window.ethereum in a TypeScript project. MetaMask injects a global API into websites visited by its users at window.ethereum
To fix this warning, and corresponding compile error, add this declaration at the top level of your file, after imports.
declare var window: any
Note, this is not the best fix as this temporarily fixes the warning by telling the TypeScript compiler to treat window as of type any hence ignore any warnings.
This sacrifices also any IntelliSense and auto-completion provided by code editor on the window object.