Async Await

ES7 Async/Await in Node. We want to make this open-source project available for people all around the world. You will learn a lot about the underlying infrastructure, but before digging into that, it is important for you to see how your code can be much cleaner and readable. Using async methods for long running tasks, like downloading data, helps keep your user interface responsive, while not using async methods, or the improper use of async/await, can cause your app’s UI to stop responding to user input until the long-running task completes. Async/await is, like promises, non blocking. For every async method a state machine is generated. If you're not familiar with promises check out one of these great resources. Eventually, we plan to permit async fn in other places, but there are some complications to be resolved first, as will be discussed shortly. I'll Get Back to You: Task, Await, and Asynchronous Methods in C# 15 Async & Await - Duration: 18. The Rust Unstable Book. On of the benefits of async/await is that it makes asynchronous code appear more like synchronous code. ES7/ES2016 Async Functions. Net is really super. But in Xamarin. WaitOne() has been replaced by Async. If you don't use it , the state machine generated by the C# compiler for the async method would not be accomplishing anything. But this is not why async functions are a step in the wrong direction. The answer is yes thanks to the ES7 proposal for Asynchronous Functions (Async/Await). a simple text & image download using the new C# 5 async and await syntax. async functions return a promise. map() Using async/await combined with map() can be a little tricky. Re: Simple. Async / Await is amazing, the mecca of working with asynchronous code in JavaScript. On of the benefits of async/await is that it makes asynchronous code appear more like synchronous code. return await Task. An application with a GUI, check the content of the queue and if an unprocessed task is there, it takes it out and processes it first. It looks like synchronous code. Tasks that used to take complex libraries or intricate promise chaining can now be done with rudimentary if statements and for loops. Also we should make the function async for them to work. On the front-end it’s another story. The async workflows can also be used with IAsyncResult, begin/end pairs, and other standard. async/await on AWS Lambda. but this really gets messy when you have a lot of async/await (which is common in WinRt code). And after this article Understanding C# async / await (2) Awaitable / Awaiter Pattern - Dixin's Blog. Exception safety Basic guarantee: if an exception is thrown, all objects involved are left in a valid state. On the front-end it’s another story. When the await is hit, it returns immediately to the caller, which in the case of an event handler is the message loop. The latest addition, in the form of async/await statements, finally made asynchronous code in JavaScript as easy to read and write as any other piece of code. async and await keywords are introduced in C#5 for asynchronous programming. Which means that we have to add a lot of this support ourselves. async / await is the newer replacement to BackgroundWorker, which has been used on windows forms desktop applications. It aims to make asynchronous programming easy (well, at least a little bit easier than it is today). What Developers are Saying. ConfigureAwait(false); } As a result, you can and should factor out multiple asynchronous operations where context needs to be maintained into a separate method, so you're only need to conserve the context once, instead of N times. If a promise resolves normally, then await promise returns the result. with async / await , you write less code and your code will be more maintainable than using the previous asynchronous programming methods such as using plain tasks. Writing async code via Promises and. Await works only with Promises, it does not work with callbacks. The return type of the method should be async Task (async void Task) or async Task where T is the type of object returned by the method, although async void is not recommended. Asynchronous JavaScript has never been easy. async and/or await keyword cannot work in isolation. The await keyword only works within an async function. Using async / await. 5 / C# 5 is very major changes. Await and async are used to optimise the usage of threads in a multi-user scenario, like on a web site, so that the system can handle more users. private static async Task Main (string [] args) { var stopwatch = new Stopwatch (); stopwatch. I don't want GUI will be locked until the method will finish his job. Using async / await. PEP 492 and PEP 525 introduce support for native coroutines and asynchronous generators using async / await syntax. The performance is absolutely critical in this area. The return type of the method should be async Task (async void Task) or async Task where T is the type of object returned by the method, although async void is not recommended. This enables us to invoke an async function and mix that with regular promise-based continuation as well. I know that the paid version 4+ supports async await, but it is costly. Async Components Watch a free video lesson on Vue School In large applications, we may need to divide the app into smaller chunks and only load a component from the server when it's needed. This article highlights some common mistakes, and gives advice on how to avoid these mistakes. The Async Keyword in our declaration creates the promise and Await, when placed in front of a Promise call, forces the rest of the code to wait until that Promise finishes and returns a result. This chapter will discuss async/. Introduced in Python 3. You can use it in NativeScript too, but you need this little trick to get it working. You can make GUI updates before and after the "await" command, as it is only the await command which is run asynchronously. As you will see it below, it makes writing code in JavaScript so much easier and it makes the language itself so much more powerful. What Developers are Saying. Async Await Support in TypeScript. You can only use the await keyword inside a function that is declared as async (you put the async keyword before the function keyword or before the parameters when using a callback function). These calls are re-written (at runtime or build time, as you prefer) to make the calls non-blocking! The code is much easier. Under the hood the code is still asynchronous. The await operator, which is only available inside of an async function, is where the magic happens. Async provides you with Hills to seamlessly track per-issue and per-pull request progress. CompilerServicesnamespace. The "await" option can be specified multiple times if you need to make other asyncronous calls. An example might be a critical section where two network requests should never be made concurrently. RunSynchronously timerEvent which blocks on the async object until it has completed. The code that comes after an awaited method – the continuation – is what will be executed when the awaited method returns with a result. Async/await. C#のスレッド(非同期処理)は、他の言語では見ない類稀な構文であるため、かなり難しいと思います。さらにawait / asyncを使うと、プログラムに書かれていない部分にも意識を回す必要があり、初心者には厳しい関門でしょう. Net runtime doesn’t know about async and await keywords. It uses HttpClient. Async/Await One of the goals of async/await is to make asynchronous code appear more syntactically similar to synchronous code. You might recall from the previous guide that the async keyword is actually just a way to eliminate ambiguity for the compiler with regard to await. It does not support async await at all, but you can work around this. A method marked with async starts running synchronously on the current thread. I love async/await, it's the future, but dear god debugging transpiled async/await code is a nightmare (and I'm no stranger to JS transpilers, been doing it since 2007) I'm not sure if Babel/Webpack doesn't support source maps with async/await, or if I don't have it configured right, but if someone has gotten it working please let me know how. To write an async test, just use the async keyword in front of the function passed to test. Better Performance from Async Operations The C# language has had support for the async and await keywords (and yet another new way to perform asynchronous operations) for a while now. It misunderstands the nature of the types involved—the method signature is not the right way to express the intended semantics. 5 and use async and await… What is the ConfigureAwait() for? It was introduced since. As part of this push, I’m happy to announce we’ve formed a async-await. So the next thing that we want to do is actually having something that we can await, in our case this is the call to GetAllOrders. Today while working on one of my WPF application I encountered a strange, rather an unexpected, issue with async/await and Linq extensions where Async/Await didn't worked…. And after a while in the background they loose their color and they look like errors. Let's build a simple WPF application with a button and a textbox. 经常会看到有了 async-await、promise 还有必要学习吗、async await优于promise的几个特点,接收了这些信息后,就蒙圈了。现在才知道,async-await是promise和generator的语法糖。只是为了让我们书写代码时更加流畅. That's all the async keyword does! It does not run this method on a thread pool thread, or do any other kind of magic. NET , async , C# , WinRT By introducing the new async/await keywords in C# 5 and by adding asynchronous APIs in. When we are dealing with UI and on button click, we use a long running method like reading a large file or something else which will take a long time, in that case, the entire application must wait to complete the whole task. In yesterday’s post, I mentioned that there is a performance penalty of using the new Async/Await feature inside of loops. Method definition should include the keyword async, this keyword by itself doesn't do anything except enabling you to use the keyword await within the method. 12 when we firstly developed and at that moment we tried our best to prevent our code from the callback hell. Let’s take a look at the examples of each of these solutions and reflect on the evolution of asynchronous programming in JavaScript. Using Async with Nancy. In computer programming, the async/await pattern is a syntactic feature of many programming languages that allows an asynchronous, non-blocking function to be structured in a way similar to an ordinary synchronous function. I might not be describing something highly technical but would like to share my learning. An asynchronous function in Python is typically called a 'coroutine', Yield from. async await:The async and await keywords in C# are the heart of async programming. ES7 Async/Await in Node. Async keyword is used to call the function/method as asynchronously. published at 18. I don't want GUI will be locked until the method will finish his job. Stackify's Prefix & Retrace products both have excellent support for applications using C# async await. await接受thenables(好吧我这个渣渣并不知道thenables该如何翻译,有人能告知吗?. Exception safety Basic guarantee: if an exception is thrown, all objects involved are left in a valid state. It is a recommended practise to name the asynchronous methods with ending string as Async (WriteAsync(), ReadAsync()). C# 8 adds Async Streams, which allows an async method to return multiple values broadening its usability. It's important to keep in mind that this is just syntactic sugar though. You should be careful when using it multiple times in a row as the Await keyword stops the execution of all the code after it. The goal of async/await is to help software developers write asynchronous code as if it were synchronous code, or in a synchronous looking style. Developers from synchronous programming background will feel at home while using async and await. Let's say I have an API call that returns all the users from a database and takes some amount of time to complete. As with every great tool, it is our responsability to understand how to use it for the best. resolve(), so you can safely await non-native promises. all or util. Threading is. Async/await is built on top of promises and non blocking. Async code uses Task and Task, which are constructs used to model work being done in the background. This code basically just runs the two sample methods synchronously (despite the async/await cruft in the code). The purpose of async/await functions is to simplify the behavior of using. async/await es6 javascript promise. How To Unit Test Async Methods with MSTest, XUnit and VS11 Beta Mar 3, 2012 • Richard Banks MSTest finally got some love with the Visual Studio 11 Beta and one of those changes was to enable tests to run asynchronously using the async and await keywords. Few points about async/await: | Courtesy. I love the new way of writing async functions in a more synchronous way with async - await. NET Core, etc. In most cases async/await is the best choice, since it makes the code maintainable and it's supported by Node. NetMQRuntime is also a NetMQScheduler and SyncrhonizationContext, so any awaited function is continuing on the runtime's thread. By pressing the button we call for some slow method (I named it SlowDude :). The async keyword turns a method into an async method, which allows you to use the await keyword in its body. Using async methods for long running tasks, like downloading data, helps keep your user interface responsive, while not using async methods, or the improper use of async/await, can cause your app’s UI to stop responding to user input until the long-running task completes. Asynchronous methods defined using the async keyword are called async methods. The async and await keywords have been a part of C# language since version 5. I dare to say that, aside from being superficially simple, async/await is the most important feature introduced with ES6. js by @boucher. Async/await makes asynchronous code look and behave a little more like synchronous code. For compatibility with older versions of Python, you can use “decorated” or “yield-based” coroutines using the tornado. RunSynchronously timerEvent which blocks on the async object until it has completed. Older browsers or Node. 4) and its two keywords, async and await, serve different purposes but come together to help you declare, build, execute, and manage asynchronous code. The purpose of async/await functions is to simplify the behavior of using. In fact whatever problem we solved using promise in this article, we will now solve those problems using. The answer is yes thanks to the ES7 proposal for Asynchronous Functions (Async/Await). next()方法执行)。generator是async函数的基础,更具灵活性。. This has a couple of effects— now, myAsyncFunction returns a promise, and any synchronous code we want to run has to be pulled out of the function entirely. Async await multiple API calls. We make an async function finishMyTask and use await to wait for the result of operations such as queryDatabase, sendEmail, logTaskInFile etc. In that case it has no effect on a method's signature or public metadata; it affects only what happens inside the method. The asyncio Package and async/await. The async is a specifier which directs the compiler to orchestrate automatically during the compilation to change its behavior and with the use of contextual keyword await inside an async method it makes the life of a regular programmer really easy to create more responsive code. CompilerServicesnamespace. One great example that Unity does provide support for TAP:. The keywords async and await make use of TPL internally. Net's async/await implementation it is worthwhile to take time to understand some of its implications. Async/await is great for avoiding blocking while potentially time-consuming work is performed in a. Instead of using Thread Sleep or HttpClient to demonstrate async await, I have word count kind of example. Async/await is, like promises, non blocking. I hope you have learned something new! If you found. …Similar to promises,…it makes a synchronous code look even more synchronous. It is a recommended practise to name the asynchronous methods with ending string as Async (WriteAsync(), ReadAsync()). 7, context managers that used thread local variables had the chance to bleed values across executions, potentially creating bugs that are difficult to find. Async/await is a new way to write asynchronous code. Let's take a look at the examples of each of these solutions and reflect on the evolution of asynchronous programming in JavaScript. Let’s take an example of a Xamarin application were the user order a coffee by pressing a button in the application. js opens up a host of powerful design patterns. The await operator, which is only available inside of an async function, is where the magic happens. 让我们以 async 这个关键字开始。它可以被放置在一个函数前面,像下面这样:. When present, it specifies that the script will be executed asynchronously as soon as it is available. Conclusion In this article, we have learned the difference between synchronous and asynchronous JavaScript, and also learned how to use a callback, promises and async/await. Await can only be used inside an async block. You might have already heard about asynchronous programming, either in. That promise is rejected in the case of uncaught exceptions, and it’s otherwise resolved to the return value of the async function. The following example shows a simple function that uses these. The latest addition, in the form of async/await statements, finally made asynchronous code in JavaScript as easy to read and write as any other piece of code. I was working on a project at work and was running code that we hadn't properly run since we upgraded our project to. That means that async/await is supported in the current branch, but it will not fall under LTS (currently at v6. 5 supports the async and await keywords across all platforms (WinRT,. Async await is a cleaner way to express the same ideas as callbacks and do not incur the performance overhead of synchronous code. C# async는 컴파일러에게 해당 메서드가 await를 가지고 있음을 알려주는 역활을 한다. A promise by search. However with the introduction of the async/await keywords, this plumbing has been pushed down to the language level. It is easier to read and write. A beautiful picture of a waterfall (by Jeffrey Workman) async/await is freaking awesome,. How async await Works in C#. Now, using async/await, our code might look like the function below. These coro trampolines are a clever hack, but the async/await syntax allows these two completely distinct language features to become truly orthogonal. async라고 표시된 메서드는 await를 1개 이상 가질 수 있는데, 하나도 없는 경우라도 컴파일은 가능하지만 Warning 메시지가 표시된다. asyncio is a library to write concurrent code using the async/await syntax. Find out how. A brief idea about control flow for those who does not know about control flow. The (new) Best Way: Async / Await. js opens up a host of powerful design patterns. Async await in AngularJS Posted by Tiddo Langerak on Nov 16, 2015 ES7 introduces async functions , which allow you to write asynchronous code with a synchronous syntax. Bottom line, be careful of how you structure and re structure your code when using async/await. The trick is create a instance of a. With the Async and Await keywords in VB. What Developers are Saying. Be careful out there. When the await keyword is applied, it suspends the calling method and yields control back to its caller until the awaited task is complete. In theory this solution could hold 10 000 connections and still use only 10 threads. Future with Async & Await. Posted by Sanjeev February 11, 2014 5 Comments on C# synchronization blocks containing await or how to lock a block with an await Recently working on a project, I came across a scenario where I needed to lock a block so that only one thread could enter the block at a time. Be careful out there. While async/await can greatly increase the number of requests your application can work on at once, there is a cost to using it. Here’s the starting code. What I'm saying is that if we are going to build special support for async/await we should take a step back and see what we could do if they weren't built on top of promises. The async attribute is a boolean attribute. As of last month, its an official feature of the language and widely supported. Before async/await, if it needs to be made sure that the functions are running in the desired sequence, that is one after the another, chain them one after the another or register callbacks. I found out the hard way a few days ago that async/await and the Task Parallel Library don't mix very well. And after a while in the background they loose their color and they look like errors. Async/Await was created to simplify the process of working with and writing chained promises. The code that comes after an awaited method – the continuation – is what will be executed when the awaited method returns with a result. For a while, we used callbacks. Based on how async/await works, your button click handler should not block the UI from updating (the stuff that is outside of the handler). Run, async programming is better than BackgroundWorker for CPU-bound operations because async programming separates the coordination details of running your code from the work that Task. They make code that uses threads easier to read. However, each user will still need to wait for the underlying process to execute regardless of which thread it is executed on. That doesn't mean abandoning them completely from the language. The Async-Await feature in. async/await are very useful tools when it comes to cleaning up asynchronous javascript code. However, with Python 3. js and modern browsers. 让我们以 async 这个关键字开始。它可以被放置在一个函数前面,像下面这样:. Format() 方法。. Previous options for asynchronous code are callbacks and promises. On of the benefits of async/await is that it makes asynchronous code appear more like synchronous code. async/await 是写异步代码的新方式,以前的方法有回调函数和Promise。 async/await 是基于 Promise 实现的,它不能用于普通的回调函数。 async/await 与 Promise 一样,是非阻塞的。 async/await 使得异步代码看起来像同步代码,这正是它的魔力所在。 Async/Await 语法. It actually uses promises behind the scenes, so you can think of async/await as syntactic sugar over promises. Async/await is great for avoiding blocking while potentially time-consuming work is performed in a. The middle chapters discuss key utilities and control-flow tools you can use when writing async code, and describe best-practices for structuring libraries and applications to maximize performance and reusability. 「async/await」是一种以更舒适的方式使用 promises 的特殊语法,同时它也更易于理解和使用。 Async functions. But as async / await is a rather new concept in the world of JavaScript, not too many examples are based on it yet. public async Task GetUserNameAsync(){ }. On of the benefits of async/await is that it makes asynchronous code appear more like synchronous code. This method receives the context as the first argument, you can use it to fetch some data and Nuxt. While I did my series about the papers for Bristol, there was one paper, which I personally found a bit weird. Asynchronous code that calls a web service is pretty common these days. To write an async test, just use the async keyword in front of the function passed to test. Scott Hanselman shows how to use Async and Await support in ASP. coroutine decorator. So async / await is really just giving us the means to make asynchronous code look very similar to normal sequential execution logic, hiding the underlying complexities. For example, you can write the following in plain JavaScript:. 0 and even. Update 2019-06-28: Fixed a problem where the loop got closed prematurely, added better progress messages, tested on Python 3. This PEP proposes to add asynchronous versions of list, set, dict comprehensions and generator expressions. Testing Asynchronous Code with MochaJS and ES7 async/await Nov 11th 2015 (Comments) A JavaScript project I'm working on recently underwent a pretty good refactor. async and await are keywords you can use in Dart, against a Future. If the promise rejects, it throws with the rejection value, so you can deal with it using catch. ContinueWith/Wait. 5 async/await feature provides an opportunity for improving the scalability and performance of applications, particularly where tasks are more effectively done in parallel. async/await on AWS Lambda. async / await is the newer replacement to BackgroundWorker, which has been used on windows forms desktop applications. Asynchronous programming is essential to the modern web and at last JavaScript programmers have the tools to do the job – the Promise object and the async and await commands. When present, it specifies that the script will be executed asynchronously as soon as it is available. This chapter will discuss async/. async function: An async function is a function labeled with the async keyword. Async, Await. When a function is declared as async it is then able to yield execution to the calling code while it awaits for a promise to be resolved. NET Framework resources,. Async/Await was created to simplify the process of working with and writing chained promises. 7, context managers that used thread local variables had the chance to bleed values across executions, potentially creating bugs that are difficult to find. We all have read and worked on Async/Await and that too many a times. async라고 표시된 메서드는 await를 1개 이상 가질 수 있는데, 하나도 없는 경우라도 컴파일은 가능하지만 Warning 메시지가 표시된다. The following Windows Forms example illustrates the use of await in an async method, WaitAsynchronouslyAsync. and more specifically at the example included, it explains your situation a bit. While small, this overhead can cause slowdowns if you abuse async/await. The state machine generated by async/await is not the same as Task. The performance is absolutely critical in this area. One interesting implementation detail around async await is that exceptions and errors are handled just like you were to handle them in synchronous code using a try/catch. Async/Await is already available in most major browsers. Asynchronous code – code which frustrates and demoralizes even the most advanced of developers, is taking a huge leap forward in terms of usability. A couple of months ago async/await landed in V8, the JavaScript engine. It all but. Async/await makes asynchronous code look and behave a little more like synchronous code. A method can return async Task, Task, or void. This is how the first example looks without EA Async. With the Async and Await keywords in VB. Overview; Getting Started; Tools; API Reference. If you start working with the async and await keywords, you should note that you don't preclude the use of raw Promises within your TypeScript applications. NOTE: You're mileage may vary with the async/await and mocha tests with promises. 1 releases of C#) have an async Main method to start the process. Asynchronous functions are prefixed with the async keyword; await suspends the execution until an asynchronous function return promise is fulfilled and unwraps the value from the Promise returned. Deceptive simplicity of async and await January 23rd, 2012 // Posted in. NET page uses the Async and Wait keywords to run code asynchronously. The IIS on client OS seems to has a limitation of concurrent request, here is the article which explain the reason why your application not working:. Format() 方法。. This article highlights some common mistakes, and gives advice on how to avoid these mistakes. As far as browsers go, async functions are now supported by all main vendors (sans IE). NET application, but there are overheads associated with running an async method: the current execution context has to be captured, there is a thread transition, and a state machine is built through which your code runs. It all but. Without EA Async. As briefly mentioned earlier support for await/async in NUnit 2 goes beyond test methods. The performance is absolutely critical in this area. Although originally designed for use with Node. return await Task. A simple example would be:. private static async Task Main (string [] args) { var stopwatch = new Stopwatch (); stopwatch. I using socket extensively lately to build real-time data transport. The async modifier tell to the compiler to treat a await as a keyword. 说async await是gen函数的语法糖我觉得不对,应该说async await是generator中所有yield的自动执行(generator是需要手动执行,通过. From Wikipedia: direct style is the usual style of sequential programming, in which control is passed implicitly by simply going to the next line. The following Windows Forms example illustrates the use of await in an async method, WaitAsynchronouslyAsync. async 和 await 出现在C# 5. The keyword await makes JavaScript wait until that promise settles and returns its result. js will merge it with the component data. It can be applied to the function by putting it at the front of the definition: async def ping_server(ip): # ping code here. The user of the framework can implement sequences very nice, readable and debugable. doing some calculations while fetching some data from I/O. Await keyword is used to pause async function execution until a Promise is fulfilled, that is resolved or rejected, and to resume execution of the asyncfunction after fulfillments. Personally I think it's a shame we got Generators in ES6 instead of this. You CANNOT use await without using the async declaration on the method signature. What await does is to return the result of the operation immediately and synchronously if the operation has already completed or, if it hasn't, to schedule a continuation to execute the remainder of the async method and then to return control to the caller. Now, using async/await, our code might look like the function below. This site uses cookies for analytics, personalized content and ads. Note: An async method will be run synchronously if it does not contain the await keyword. Designing APIs that leverage async/await can seem easy at first but if you don’t impose a few standards during the power dev phase of a project, when…. Makes it always return a promise. Asynchronous JavaScript has never been easy. Introduced in Python 3. They may be promises internally but apart from various method names like Promise. Async/await makes asynchronous code look and behave a little more like synchronous code. net tasks unit-testing c# mocking moq multi-threaded await-async. Async await in AngularJS Posted by Tiddo Langerak on Nov 16, 2015 ES7 introduces async functions , which allow you to write asynchronous code with a synchronous syntax. An Async Primer By Bill Wagner August 2012 Introduction The C# 5. js since version 7. Angular Tutorial with Async and Await January 27th 2017 Async TypeScript Angular In version 2. Learning SynchronizationContext, async, and await Understand the core concepts behind asynchronous programming to build applications that are responsive. Every Promise can be rewritten using async/await and vice versa. Here is how you'd write the same examples from before: Here is how you'd write the same examples from before:. …So let's go back to our database…and network. hapi — v17 Upgrade Guide (Your Move to async/await) by Marcus Pöhls on November 02 2017 , tagged in hapi , Node. Async - await. async / await is the newer replacement to BackgroundWorker, which has been used on windows forms desktop applications. That promise is rejected in the case of uncaught exceptions, and it’s otherwise resolved to the return value of the async function. Async functions are defined by placing the async keyword in front of a function, such as: async fetchdata(url){ // Do something // Always returns a promise } This does two things: It causes the function to always return a promise whether or not you explicitly return something, so you can call then() on it for example. async/await is cool. I won’t be going into that level of detail now, nor will I explore the subtleties of IO and CPU bound operations. JavaScript owes its excellent single-threaded. asyncData is called every time before loading the component (only for pages components). As the title of this post points out, the better solution is "Don't block on async code". Here’s the starting code. The fact-checkers, whose work is more and more important for those who prefer facts over lies, police the line between fact and falsehood on a day-to-day basis, and do a great job. Today, my small contribution is to pass along a very good overview that reflects on one of Trump’s favorite overarching falsehoods. Namely: Trump describes an America in which everything was going down the tubes under  Obama, which is why we needed Trump to make America great again. And he claims that this project has come to fruition, with America setting records for prosperity under his leadership and guidance. “Obama bad; Trump good” is pretty much his analysis in all areas and measurement of U.S. activity, especially economically. Even if this were true, it would reflect poorly on Trump’s character, but it has the added problem of being false, a big lie made up of many small ones. Personally, I don’t assume that all economic measurements directly reflect the leadership of whoever occupies the Oval Office, nor am I smart enough to figure out what causes what in the economy. But the idea that presidents get the credit or the blame for the economy during their tenure is a political fact of life. Trump, in his adorable, immodest mendacity, not only claims credit for everything good that happens in the economy, but tells people, literally and specifically, that they have to vote for him even if they hate him, because without his guidance, their 401(k) accounts “will go down the tubes.” That would be offensive even if it were true, but it is utterly false. The stock market has been on a 10-year run of steady gains that began in 2009, the year Barack Obama was inaugurated. But why would anyone care about that? It’s only an unarguable, stubborn fact. Still, speaking of facts, there are so many measurements and indicators of how the economy is doing, that those not committed to an honest investigation can find evidence for whatever they want to believe. Trump and his most committed followers want to believe that everything was terrible under Barack Obama and great under Trump. That’s baloney. Anyone who believes that believes something false. And a series of charts and graphs published Monday in the Washington Post and explained by Economics Correspondent Heather Long provides the data that tells the tale. The details are complicated. Click through to the link above and you’ll learn much. But the overview is pretty simply this: The U.S. economy had a major meltdown in the last year of the George W. Bush presidency. Again, I’m not smart enough to know how much of this was Bush’s “fault.” But he had been in office for six years when the trouble started. So, if it’s ever reasonable to hold a president accountable for the performance of the economy, the timeline is bad for Bush. GDP growth went negative. Job growth fell sharply and then went negative. Median household income shrank. The Dow Jones Industrial Average dropped by more than 5,000 points! U.S. manufacturing output plunged, as did average home values, as did average hourly wages, as did measures of consumer confidence and most other indicators of economic health. (Backup for that is contained in the Post piece I linked to above.) Barack Obama inherited that mess of falling numbers, which continued during his first year in office, 2009, as he put in place policies designed to turn it around. By 2010, Obama’s second year, pretty much all of the negative numbers had turned positive. By the time Obama was up for reelection in 2012, all of them were headed in the right direction, which is certainly among the reasons voters gave him a second term by a solid (not landslide) margin. Basically, all of those good numbers continued throughout the second Obama term. The U.S. GDP, probably the single best measure of how the economy is doing, grew by 2.9 percent in 2015, which was Obama’s seventh year in office and was the best GDP growth number since before the crash of the late Bush years. GDP growth slowed to 1.6 percent in 2016, which may have been among the indicators that supported Trump’s campaign-year argument that everything was going to hell and only he could fix it. During the first year of Trump, GDP growth grew to 2.4 percent, which is decent but not great and anyway, a reasonable person would acknowledge that — to the degree that economic performance is to the credit or blame of the president — the performance in the first year of a new president is a mixture of the old and new policies. In Trump’s second year, 2018, the GDP grew 2.9 percent, equaling Obama’s best year, and so far in 2019, the growth rate has fallen to 2.1 percent, a mediocre number and a decline for which Trump presumably accepts no responsibility and blames either Nancy Pelosi, Ilhan Omar or, if he can swing it, Barack Obama. I suppose it’s natural for a president to want to take credit for everything good that happens on his (or someday her) watch, but not the blame for anything bad. Trump is more blatant about this than most. If we judge by his bad but remarkably steady approval ratings (today, according to the average maintained by 538.com, it’s 41.9 approval/ 53.7 disapproval) the pretty-good economy is not winning him new supporters, nor is his constant exaggeration of his accomplishments costing him many old ones). I already offered it above, but the full Washington Post workup of these numbers, and commentary/explanation by economics correspondent Heather Long, are here. On a related matter, if you care about what used to be called fiscal conservatism, which is the belief that federal debt and deficit matter, here’s a New York Times analysis, based on Congressional Budget Office data, suggesting that the annual budget deficit (that’s the amount the government borrows every year reflecting that amount by which federal spending exceeds revenues) which fell steadily during the Obama years, from a peak of $1.4 trillion at the beginning of the Obama administration, to $585 billion in 2016 (Obama’s last year in office), will be back up to $960 billion this fiscal year, and back over $1 trillion in 2020. (Here’s the New York Times piece detailing those numbers.) Trump is currently floating various tax cuts for the rich and the poor that will presumably worsen those projections, if passed. As the Times piece reported: