docs(README): when patching global context, patch TextDecoder and TextEncoder too

[jtomaszewski]

After following the README on patching the global context, node-fetch fails to me in jest jsdom environment on node v16.16.0 with following error:

TextDecoder is not defined

      Cause: ReferenceError: TextDecoder is not defined
      at Response.TextDecoder (node_modules/node-fetch/src/body.js:159:14)
      at call (node_modules/@babel/runtime/helpers/regeneratorRuntime.js:44:17)
      at Generator.tryCatch (node_modules/@babel/runtime/helpers/regeneratorRuntime.js:125:22)
      at Generator._invoke [as next] (node_modules/@babel/runtime/helpers/regeneratorRuntime.js:69:21)
      at asyncGeneratorStep (node_modules/@babel/runtime/helpers/asyncToGenerator.js:3:24)
      at asyncGeneratorStep (node_modules/@babel/runtime/helpers/asyncToGenerator.js:22:9)

That's probably because node-fetch in https://github.com/node-fetch/node-fetch/blob/main/src/body.js#L159 refers to TextDecoder using a global reference, which doesn't exist in my environment.

Changes

In recommended script in README that patches the global context, add TextDecoder and TextEncoder to the global context too.

I also removed a few unnecessary imports from it that weren't used at all.

Additional information

• I updated readme

[jimmywarting]

Since this is just readme and no breaking changes, then i would now have suggested another approach.

using conditional lazy top level import() and maybe Nullish coalescing assignment (??=) in order to not load it in vain

So maybe something like this:

// fetch-polyfill.js
globalThis.fetch || await import('node-fetch').then(mod => {
  globalThis.fetch = mod.default
  globalThis.Blob ??= mod.Blob
  globalThis.File ??= mod.File
  globalThis.FormData ??= mod.FormData
  globalThis.Headers = mod.Headers
  globalThis.Request = mod.Request
  globalThis.Response = mod.Response
})

globalThis.TextDecoder || import('node:util').then(util => {
  globalThis.TextDecoder ??= util.TextDecoder
  globalThis.TextEncoder ??= util.TextEncoder
})

// index.js
(globalThis.TextDecoder && globalThis.fetch) || await import('./fetch-polyfill.js')