Top-level JSON arrays are interpreted as objects

[Rush]

Support plan

• which support plan is this issue covered by? Community
• is this issue currently blocking your project? No
• is this issue affecting a production system? No

Context

• node version: 14.x
• module (formidable) version: 1.2.2
• environment (e.g. node, browser, native, OS): node

What are you trying to achieve or the steps to reproduce?

const http = require('http');
const formidable = require('formidable');

const server = http.createServer((req, res) => {
  const form = formidable({ multiples: true });

  form.parse(req, (err, fields, files) => {
    if (err) {
      res.writeHead(err.httpCode || 400, { 'Content-Type': 'text/plain' });
      res.end(String(err));
      return;
    }
    console.log('Got fields', fields);
    res.writeHead(200, { 'Content-Type': 'application/json' });
    res.end(JSON.stringify({ fields, files }, null, 2));
  });
});

server.listen(9090, async () => {
  const res = await require('node-fetch')('http://localhost:9090/post', { method: 'POST', headers: { "Content-Type": "application/json" }, body: `[{ "foo": "bar" } ]` });
  console.log('Res', await res.json());
  process.exit(0);
});

What was the result you got?

JSON top-level array was interpreted as an object with '0' as key.

» node index.js
Got fields { '0': { foo: 'bar' } }
Res { fields: { '0': { foo: 'bar' } }, files: {} }

What result did you expect?

Expected to receive an array. Arrays shouldn't be interpreted as objeccts.

Got fields [ { foo: 'bar' } ]

[GrosSacASac]

Yes, also top level numbers and strings are not supported I think

[Rush]

Not sure if numbers and strings are universally considered valid JSON but top-level arrays definitely are as per this SO answer https://stackoverflow.com/a/3833312 which links to respective RFCs.

[GrosSacASac]

json.org also and every JS implementation