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Easy-peasy-lemon-squeezy iterating non-standard stream implementations...
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| // For non-standard streams — APIs that stream but the library exposes something else and not the underlying Node.js stream, e.g `xml-stream` and `xml-stream-saxjs`, — you can use the following to perform standard `for await of...` iteration over each item emitted in events. | |
| const sleep = require('./sleep'); | |
| module.exports = async function* iterateNonStandardStream({ | |
| endEvent = 'end', | |
| errorEvent = 'error', | |
| itemEvent, | |
| stream, | |
| timeout = 900000 | |
| }) { | |
| const queue = []; | |
| let done = false; | |
| let error; | |
| const tid = setTimeout(() => { | |
| error = new Error('TimeoutError: Iterating Non-Standard Stream.'); | |
| done = true; | |
| }, timeout); | |
| stream.on(itemEvent, (item) => queue.push(item)); | |
| stream.on(endEvent, () => { | |
| done = true; | |
| clearTimeout(tid); | |
| }); | |
| stream.on(errorEvent, (e) => { | |
| error = e; | |
| done = true; | |
| }); | |
| while (true) { | |
| if (queue.length && !error) { | |
| const item = queue.shift(); | |
| yield item; | |
| } | |
| else { | |
| if (error) { | |
| throw error; | |
| } | |
| if (done === true) { | |
| break; | |
| } | |
| } | |
| await sleep(); | |
| } | |
| }; |
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| const SomeTypeOfNonStandardStream = require('./some-type-of-non-standard-stream'); | |
| const iterateNonStandardStream = require('./iterate-non-standard-stream'); | |
| (async () => { | |
| const nonIterableStream = new SomeTypeOfNonStandardStream({...}); | |
| const stream = iterateNonStandardStream({ | |
| itemEvent: 'item', | |
| stream: nonIterableStream | |
| }); | |
| for await (const rawItem of stream) { | |
| // Do something with each: `rawItem` | |
| } | |
| }()); |
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| module.exports = function sleep(ms = 0) { | |
| return new Promise((res) => (ms > 0 ? setTimeout(res, ms) : setImmediate(res))); | |
| }; |
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