GET requests send data: {}, which fetch-based runtimes reject #850

SDK you're using: xero-node 20.0.0 (same in 10.2.0 through 19.3.0), axios 1.19.0, Cloudflare Workers

Describe the bug

Every generated GET method (e.g. AccountingApi.getContact, getContacts, getInvoices) builds its request options with data: {}. axios serializes that to a "{}" body. Node's http adapter tolerates it, but on runtimes where axios uses its fetch adapter (Cloudflare Workers, and anywhere Request follows the Fetch spec), creating the Request throws:

TypeError: Request with a GET or HEAD method cannot have a body.

So no GET call works on Workers, even after the token request succeeds.

Expected behavior

Requests without a body parameter omit data (or set it to undefined).

Workaround

Replace the default authentication hook, which runs on each request just before axios sends it:

xero.accountingApi.setDefaultAuthentication({
  applyToRequest: (options) => {
    if (options.method === 'GET' || options.method === 'HEAD') delete options.data;
  },
});

Related: #737 (same cause, seen through nock), #740 (fetch adapter support).