graphql-yoga/esm/plugins/result-processor/multipart.js

import { isAsyncIterable } from '@envelop/core';
import { DEFAULT_MULTIPART_CONTENT_TYPE } from '@graphql-tools/utils';
import { handleMaybePromise } from '@whatwg-node/promise-helpers';
import { fakePromise } from '@whatwg-node/server';
import { getResponseInitByRespectingErrors } from '../../error.js';
import { jsonStringifyResultWithoutInternals } from './stringify.js';
export function processMultipartResult(result, fetchAPI, acceptedMediaType = DEFAULT_MULTIPART_CONTENT_TYPE) {
    const headersInit = {
        Connection: 'keep-alive',
        'Content-Type': acceptedMediaType,
        'Transfer-Encoding': 'chunked',
    };
    const responseInit = getResponseInitByRespectingErrors(result, headersInit);
    let iterator;
    const textEncoder = new fetchAPI.TextEncoder();
    const readableStream = new fetchAPI.ReadableStream({
        start(controller) {
            if (isAsyncIterable(result)) {
                iterator = result[Symbol.asyncIterator]();
            }
            else {
                let finished = false;
                iterator = {
                    next: () => {
                        if (finished) {
                            return fakePromise({ done: true, value: null });
                        }
                        finished = true;
                        return fakePromise({ done: false, value: result });
                    },
                };
            }
            controller.enqueue(textEncoder.encode('\r\n'));
            controller.enqueue(textEncoder.encode(`---`));
        },
        pull(controller) {
            return handleMaybePromise(() => iterator.next(), ({ done, value }) => {
                if (value != null) {
                    controller.enqueue(textEncoder.encode('\r\n'));
                    controller.enqueue(textEncoder.encode('Content-Type: application/json; charset=utf-8'));
                    controller.enqueue(textEncoder.encode('\r\n'));
                    const chunk = jsonStringifyResultWithoutInternals(value);
                    const encodedChunk = textEncoder.encode(chunk);
                    controller.enqueue(textEncoder.encode('Content-Length: ' + encodedChunk.byteLength));
                    controller.enqueue(textEncoder.encode('\r\n'));
                    controller.enqueue(textEncoder.encode('\r\n'));
                    controller.enqueue(encodedChunk);
                    controller.enqueue(textEncoder.encode('\r\n'));
                    controller.enqueue(textEncoder.encode('---'));
                }
                if (done) {
                    controller.enqueue(textEncoder.encode('--\r\n'));
                    controller.close();
                }
            }, err => {
                controller.error(err);
            });
        },
        cancel(e) {
            if (iterator?.return) {
                return handleMaybePromise(() => iterator.return?.(e), () => { });
            }
        },
    });
    return new fetchAPI.Response(readableStream, responseInit);
}