Error TS2339: Property ‘entries’ does not exist on type ‘FormData’

You need to add “dom.iterable” to your lib list in tsconfig.json, for example:

{
  "compilerOptions": {
    "baseUrl": ".",
    "outDir": "build/dist",
    "module": "esnext",
    "target": "es6",
    "lib": [
      "es2019",
      "dom",
      "dom.iterable" // <- there you are
    ],
    // ...
}