upload.ts

// @ts-nocheck
import { extractFiles } from 'extract-files'
import { Upload } from 'graphql-upload'
import FormData from './form'
import { print } from 'graphql'
import { AsyncExecutor, Subscriber } from '@graphql-tools/delegate';

export async function buildUploadExecutor(endpoint: string, customFetch: any, extraHeaders: any) : Promise<{ executor: AsyncExecutor; subscriber: Subscriber }> {
  const executor = async ({ document, variables }: any) => {
    const vars = Object.assign({}, variables)
    const { clone, files } = extractFiles(vars, 'variables', (v: any) => v instanceof Upload)
    const map = Object.fromEntries(Array.from(files.values()).map((p, i) => [i, p]))
    const uploads = new Map(Array.from(files.keys()).map((u, i) => [i, u]))
    const form = new FormData()
    form.append('operations', JSON.stringify({
      query: print(document),
      variables: clone,
    }))
    form.append('map', JSON.stringify(map))
    for (let [i, u] of uploads) {
      const upload = await u.promise
      const stream = upload.createReadStream()
      form.append(i.toString(), stream, {
        filename: upload.filename,
        contentType: upload.mimetype,
      })
    }
    const result = await customFetch(endpoint, {
      method: 'POST',
      headers: extraHeaders,
      body: form,
    });
    return result.json();
  }
  return {
    executor: executor,
    subscriber: null,
  }
}