async-await

问题 I really like the async/await pattern in Dart. It allows me to write readable methods. But, there are a couple of things that are problematic, one in particular, I don't know hot to manage at all. The problem is that with async and multiple await inside a method, we introduce concurrency in the method. For example If I have a method: Future<int> foo(int value) async { await foo2(); await foo3(); await foo4(); int ret = foo5(value); return ret; } Well, this is a really simple example. The

问题 I'm seeing this behavior in Node and Chrome: setTimeout(()=>{ console.log('timeout') }, 0) Promise.resolve().then(()=>{ console.log('promise') }) console.log('sync') // output order: // sync // promise // timeout My question is, is this consistent behavior? I.e, according to spec, does a then or await on a memoized/already resolved promise always fire before setTimeout(fn, 0) ? I want to use this in something like the following, returning one thing if I have a memoized result in my promise

问题 I'm trying to load a very large image (about 16000x7000 pixel) into a Material, and I've tried to load it asynchronously. My first try was to create a task that loaded the BitmapImage and then use it into the material: var bmp = await System.Threading.Tasks.Task.Run(() => { BitmapImage img = new BitmapImage(new Uri(path)); ImageBrush brush = new ImageBrush(img); var material = new System.Windows.Media.Media3D.DiffuseMaterial(brush); material.Freeze(); return material; }); BackMaterial = bmp;

问题 I'm not entirely sure what I am doing here is correct as I haven't used the async / await methods much and was going to learn more in a small application. Code: public async Task ImportURLs() { // read contents of the chosen combobox platform ... var comp = File.ReadAllText(@"Platforms\" + comboBoxPlatform.Text).Split('|'); var reg = comp[0]; var fl1 = comp[1]; var fl2 = comp[2]; string line; OpenFileDialog ofd = new OpenFileDialog { Filter = "URLs.txt|*.txt" }; if (ofd.ShowDialog() ==

问题 I'm not entirely sure what I am doing here is correct as I haven't used the async / await methods much and was going to learn more in a small application. Code: public async Task ImportURLs() { // read contents of the chosen combobox platform ... var comp = File.ReadAllText(@"Platforms\" + comboBoxPlatform.Text).Split('|'); var reg = comp[0]; var fl1 = comp[1]; var fl2 = comp[2]; string line; OpenFileDialog ofd = new OpenFileDialog { Filter = "URLs.txt|*.txt" }; if (ofd.ShowDialog() ==

问题 @Input() list: string[]; ngOnInit() : void { this.valueMap = new Map<any, any>(); this.getDataFromService(); this.buildContainer(); } private getDataFromService(): void { this.list.forEach(value-> { this.fetchService(value).subscribe(data ->{ this.valueMap.set(value,data); } ) }) } private buildContainer(): void { console.log(this.valueMap.size); // shows always 0 even when service returns the data } Now thing is that I have to use this valueMap in the method buidlContainer() , hence I need

问题 @Input() list: string[]; ngOnInit() : void { this.valueMap = new Map<any, any>(); this.getDataFromService(); this.buildContainer(); } private getDataFromService(): void { this.list.forEach(value-> { this.fetchService(value).subscribe(data ->{ this.valueMap.set(value,data); } ) }) } private buildContainer(): void { console.log(this.valueMap.size); // shows always 0 even when service returns the data } Now thing is that I have to use this valueMap in the method buidlContainer() , hence I need

问题 I would like to replicate the behavior and ergonomics of taking a closure/function as an argument much like map does: iterator.map(|x| ...) . I've noticed that some library code allows passing in async functionality, but this method doesn't allow me to pass in arguments: pub fn spawn<F, T>(future: F) -> JoinHandle<T> where F: Future<Output = T> + Send + 'static, T: Send + 'static, spawn(async { foo().await }); I'm hoping to do one of the following: iterator.map(async |x| {...}); async fn a(x:

问题 I would like to replicate the behavior and ergonomics of taking a closure/function as an argument much like map does: iterator.map(|x| ...) . I've noticed that some library code allows passing in async functionality, but this method doesn't allow me to pass in arguments: pub fn spawn<F, T>(future: F) -> JoinHandle<T> where F: Future<Output = T> + Send + 'static, T: Send + 'static, spawn(async { foo().await }); I'm hoping to do one of the following: iterator.map(async |x| {...}); async fn a(x:

问题 I would like to replicate the behavior and ergonomics of taking a closure/function as an argument much like map does: iterator.map(|x| ...) . I've noticed that some library code allows passing in async functionality, but this method doesn't allow me to pass in arguments: pub fn spawn<F, T>(future: F) -> JoinHandle<T> where F: Future<Output = T> + Send + 'static, T: Send + 'static, spawn(async { foo().await }); I'm hoping to do one of the following: iterator.map(async |x| {...}); async fn a(x: