response-iterator/dist/esm/iterators/nodeStream.js

Creates an async iterator for a variety of inputs in the browser and node. Supports fetch, node-fetch, and cross-fetch

const hasIterator = typeof Symbol !== 'undefined' && Symbol.asyncIterator;
/* c8 ignore start */ export default function nodeStreamIterator(stream) {
    let cleanup = null;
    let error = null;
    let done = false;
    const data = [];
    const waiting = [];
    function onData(chunk) {
        if (error) return;
        if (waiting.length) return waiting.shift()[0]({
            value: chunk,
            done: false
        });
        data.push(chunk);
    }
    function onError(err) {
        error = err;
        const all = waiting.slice();
        all.forEach((pair)=>{
            pair[1](err);
        });
        !cleanup || cleanup();
    }
    function onEnd() {
        done = true;
        const all = waiting.slice();
        all.forEach((pair)=>{
            pair[0]({
                value: undefined,
                done: true
            });
        });
        !cleanup || cleanup();
    }
    cleanup = ()=>{
        cleanup = null;
        stream.removeListener('data', onData);
        stream.removeListener('error', onError);
        stream.removeListener('end', onEnd);
        stream.removeListener('finish', onEnd);
        stream.removeListener('close', onEnd);
    };
    stream.on('data', onData);
    stream.on('error', onError);
    stream.on('end', onEnd);
    stream.on('finish', onEnd);
    stream.on('close', onEnd);
    function getNext() {
        return new Promise((resolve, reject)=>{
            if (error) return reject(error);
            if (data.length) return resolve({
                value: data.shift(),
                done: false
            });
            if (done) return resolve({
                value: undefined,
                done: true
            });
            waiting.push([
                resolve,
                reject
            ]);
        });
    }
    const iterator = {
        next () {
            return getNext();
        }
    };
    if (hasIterator) {
        iterator[Symbol.asyncIterator] = function() {
            return this;
        };
    }
    return iterator;
} /* c8 ignore stop */