we get promises that eventually resolve to the usual{ value: any, done: boolean }object. We also get the for-await-of loop to help us with looping over async iterators. That is just like the
Since node@10.0.0, there is support for async iterators and the related for-await-of loop. These come in handy when the actual values we iterate over, and the end state of the iteration, are not known by the time the iterator method returns – mostly when working with streams. Aside fr...
While Mongoose cursors have anext()function, they arenotcurrently async iterators or async iterables. Unlike an async iterator, a Mongoose cursor returnsnullto signify the end of the cursor, not{ done: true }. In order to usefor/await/ofwith Mongoose cursors, you need to do a little work...
Section “Streams Compatibility with Async Generators and Async Iterators” in the Node.js docs Chapter “Async functions” in “Exploring JavaScript” Chapter “Asynchronous iteration” in “Exploring JavaScript”Dr. Axel RauschmayerHomepage | Mastodon...
JavaScript 中有很多种异步编程的方式。callback、promise、generator、async await 甚至 RxJS。我最初接触不同的异步模式时,曾想当然的觉得 promise 就是比 callback 好, async await 比就是比 promise 优雅,会把它们割裂起来看待。后来发现也不完全这样,各种异步模式之间其实存在着关联,也有着各自擅长的场景。
node> var fn = async.apply(sys.puts, 'one'); node> fn('two', 'three'); one two three ### nextTick(callback) Calls the callback on a later loop around the event loop. In node.js this just calls process.nextTick, in the browser it falls back to setTimeout(callback, 0), wh...
Specifically, using a combination of on('data'), on('readable'), pipe(), or async iterators could lead to unintuitive behavior. C stream.Readable Added in: v0.9.4 Event: 'close' 历史 版本更改 v10.0.0 Add `emitClose` option to specify if `'close'` is emitted on destroy. v0.9.4 ...
Consuming readable streams with async iterators JScopy (async function() { for await (const chunk of readable) { console.log(chunk); } })(); Async iterators register a permanent error handler on the stream to prevent any unhandled post-destroy errors. Creating readable streams with async gen...
When a suspendable function is called, itsthiscontext is passed through to the call to its definition. For example, whensuspendable.call(myObj, 1, 2)is executed,defnwill be called with arguments1and2and athisvalue ofmyObj. Theasyncfunction can be used to create asynchronous iterators. These...
下面从一个经典的“遗漏特性”说起,十年来我一直期待在JavaScript中看到的它——ES6迭代器(iterators)和新的for-of循环! 迭代器和for-of循环 如何遍历数组?20年前JavaScript刚萌生时,你可能这样实现数组遍历: for(varindex=0;index<myArray.length;index++){ ...