Asynchronous Programming - Reading Assignment

Javascript Programming
#422

  1. Asynchronous function takes a task gets it started, puts it on the back burner and gets on with the next task in hand while the first one is completed.

  2. Complex operations produce loads of levels and sub levels these are known as Callback Hell.

  3. Promises are known for dealing with call back hell. They can store these complex queries. They can chain them to a library and check them for errors.

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#423

  1. What is the difference between synchronous and asynchronous functions?

    Synchronous: Only one section of the code can be running at any one time

    Asynchronous: An asynchronous task can be initiated and then put aside until a later date while the code gets started on the next task on it’s to-do list.

  2. What is callback hell?

    More complex operations tend to produce even more levels and sub-levels, which is what is poetically known as callback hell.

  3. Which technique can help us solve callback hell?

    A common pattern to deal with excessive callbacks is to use promises. jQuery ships with a simple built-in promise library that enables us to chain callbacks and deal with errors.

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#424

  1. What is the difference between synchronous and asynchronous functions?
    Synchronous is when the browser won’t move on from the order of operations, left to right, up to down. Asynchronous functions are able to tasks aside until a later time while it does other functions.

  2. What is callback hell?
    It’s when several nested callback functions are needed to perform simple tasks. It complicates readability, maintenance and function.

  3. Which technique can help us solve callback hell?
    We can use promises to deal with synchronous functions and allows us to handle errors.

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#425

What is the difference between synchronous and asynchronous functions?

Synchronous is when the browser won’t respond to any JS events whatsoever while it completes the first handler.

An asynchronous task can be initiated and then put aside until a later date while our browser gets started on the next task.

What is callback hell?

more complex operations tend to produce even more levels and sub-levels, which is known as callback hell.

Which technique can help us solve callback hell?
a common pattern to deal with excessive callbacks is to use promises. jQuery ships with a simple built-in promise library that enables us to chain callbacks and deal with errors.

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#426
  1. Synchronous functions require the program’s “attention” until it is finished. Leaving it impossible for the program to do anything else.
    Asynchronous functions do not stop the whole thread, while they wait for the execution of the task to complete, they can do other work.
  2. More complex operations tend to produce even more levels and sub-levels of nesting functions, which is what is poetically known as callback hell. These nested event handlers allow for our code to become asynchronous.
  3. In the browser, a common pattern to deal with excessive callbacks is to use promises. jQuery ships with a simple built-in promise library that enables us to chain callbacks and deal with errors.
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#427

What is the difference between synchronous and asynchronous functions?
Synchronous tasks complete tasks one at a time before moving to the next task, and the asynchronous task can initiate a task then initiate other tasks while waiting on callbacks to complete earlier tasks.

What is callback hell?
The complexity of built-up callbacks in asynchronous functions.

Which technique can help us solve callback hell?
Promise libraries are built into the client browser, and Fibre packages are built into servers.

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#428
  1. Synchronous functions run in the standard control flow. A function that is written further down in the code will not execute until the one before it has completed. Asynchronous functions are able to use an event loop which waits and monitors that function until it does whatever it needs to do, meanwhile letting the rest of the code continue to execute.
  2. Call back hell is a term used to describe too many nested functions. This makes for bulky code that’s hard to read and hard to debug, as well as being more prone to errors.
  3. We can use promises, which are included in the jQuery library. This allows us to abstract away a lot of the nested functions and write simpler cleaner code.
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#429

  • What is the difference between synchronous and asynchronous functions?
    Ans: While a synchronous function is executed only when it’s turn has come in the top-to-bottom manner, an asynchronous function can be executed at any time.

  • What is callback hell?
    Ans: Source: Google “The cause of callback hell is when people try to write JavaScript in a way where execution happens visually from top to bottom.”

  • Which technique can help us solve callback hell?
    Ans: not sure

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#430
  1. Synchronous functions with multiple commands will run them one at a time, waiting for each command to finish before running the next one. Asynchronous functions with multiple commands will run the simultaneously without waiting for one command to finish before running the next.
  2. callback hell is when complex operations produce lots of levels and sub-levels of nested functions.
  3. a common pattern to deal with excessive callbacks is to use promises. jQuery ships with a
    simple built-in promise library that enables to chain callbacks and deal with errors.
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#431
  1. Synchronous(blocking) functions - only one section of code can be running at any one time(single-threading)
    Asynchronous - an asynchronous task can be initiated and then put aside until a later date while the Javascript compiler/engine gets started on the next item on the event loop.
  2. Complex operations tend to produce complex function levels and sub-levels, which is what is poetically known as callback hell.
  3. By extending the runtime, we can abstract away the asynchronicity and write code that looks sychronous.
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#432

  1. Synchronous functions block the program from executing further code because the event handler and only deal with one task at a time (single threaded). Asynchronous functions are able to handle more than one task at a time by setting the first event to wait and have another event handler execute code while the first waits for the desired input.

  2. Callback hell exists when code becomes increasingly complex and multiple callback events are needed, such as within nested functions, where callbacks are dependent on other callbacks.

  3. We can use promises to deal with callback hell, which essentially takes asynchronous code and transforms it to look like synchronous code and read like syncrhonous code.

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#433
  1. What is the difference between synchronous and asynchronous functions?
  • Synchronous functions block the program’s further execution until something is done while Asynchronous functions do not block the program and wait while the program thread does other task.
  1. What is callback hell?
  • Several nested callback functions are needed in order to perform relatively simple tasks.
  1. Which technique can help us solve callback hell?
  • Using Promises to chain callbacks and deal with errors.
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#434

  1. What is the difference between synchronous and asynchronous functions?
    asynchronous functions can run at the same time as other functions. e.a. multi threaded
    synchronous functions behave single threaded.

  2. What is callback hell?
    The problems that arise from multiple nested callback functions

  3. Which technique can help us solve callback hell?
    using the promise library in javascript.
    (Or on node-js some other libraries)

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#435

1.) The difference between synchronous and asynchronous functions is that synchronous functions happen when called upon, without needing a third party or having anything holding it up, whereas an asynchronous functions might take longer to be carried due to the need of participation from a third party. An asynchronous function can be set aside until the objective of the function is completed.
2.) Callback hell happens when code gets bogged down and complicated by callbacks and asynchronous functions. It makes a function, that should be simple, complicated.
3.) A promise is s used to solve callback hell.

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#436

  1. Synchronous functions will perform the task continuously until it in complete where as asynchronous function will perform another task while waiting for the first task to complete

  2. Callback hell is when there are too many calls waiting to come back due to the various levels of functions hence clogging up the webpage from loading

  3. JQuery has a promise library which enables us to chain callback and deal with errors

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#437

  1. what is the difference between Asynchronous and synchronous: synchronous code is executed in sequence – each statement waits for the previous statement to finish before executing. Asynchronous code doesn’t have to wait – your program can continue to run. You do this to keep your site or app responsive, reducing waiting time for the user.

  2. What is Callback hell? This is affectionately known as callback hell. The cause of callback hell is when people try to write JavaScript in a way where execution happens visually from top to bottom.

  3. Which technique can help us solve callback hell? JavaScript provides an easy way of escaping from a callback hell. This is done by event queue and promises. A promise is a returned object from any asynchronous function, to which callback methods can be added based on the previous function’s result. Promises use . then() method to call async callbacks.

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#438

1).What is the difference between synchronous and asynchronous functions?
A). JavaScript is Synchronous at its base, JavaScript is a synchronous, blocking, single-threaded language. That just means that only one operation can be in progress at a time. That’s not the entire story, though!

Although synchronous operation is often preferred, there are certain cases where it is not needed. There are even cases where synchronous operation can be detrimental to the objective. An example where synchronous operation is not really necessary is in internet browsing. Prior to AJAX (Asynchronous Javascript and XML) most webpages need to be reloaded in its entirety to change the information on a small section. With AJAX, it is now possible to update that certain section while leaving the rest of the page untouched. This is beneficial as a smaller amount of data needs to be transmitted and the user doesn’t have to endure through the whole page refreshing. AJAX is asynchronous because page updates are no longer synchronized.

Summary:
Synchronous means in time order while Asynchronous means no time order
Synchronous is preferred over asynchronous in many real world applications
Synchronous can perform worse in certain scenarios than asynchronous

Read more: Difference Between Synchronous and Asynchronous | Difference Between http://www.differencebetween.net/language/difference-between-synchronous-and-asynchronous/#ixzz6YOZsuixk

Read more: Difference Between Synchronous and Asynchronous | Difference Between http://www.differencebetween.net/language/difference-between-synchronous-and-asynchronous/#ixzz6YOOGgFqk

2).What is callback hell?

A). JavaScript programmers are talking a lot about callback hell. Callback hell is a concept that affects a JavaScript developer when he tries to perform various callbacks function one after the other. Some persons call it the pyramid of doom.
Using callbacks causes the program difficult to write and maintain. It also increases the problems of identifying the order flow, which is an obstacle when debugging, hence the famous name for this issue: Callback Hell.
3).Which technique can help us solve callback hell?

A). Promises are an option to callbacks when interacting with asynchronous code. Promises return the result value or an exception to a mistake. The heart of the promises is the.then() function, which waits for returning the promise object. The.then() function requires two optional functions as arguments and only one will ever be called depending on the state of the promise. The first method is called when the promise is fulfilled. When the promise is rejected, the second function is called.
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#439
  1. Synchronous are tasked running in a start to finish no matter what. Asynchronous function can be put aside but yet again introduced at a later date due to a special event.
  2. It’s when a function operators requires many sub-levels on sub-levels of call back creating immense complexity
  3. Promises, extending the runtime or Fibers future sub-library
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#440
  1. What is the difference between synchronous and asynchronous functions?

A synchronous task must be finished once it is started and only one can be done at any one time. Asynchronous tasks are tasks that can run in the background, or be started and returned to at a later time.

  1. What is callback hell?

Callback hell is used to describe a complex system of large numbers of nested functions which can become very difficult to understand.

  1. Which technique can help us solve callback hell?

In a browser, promises allow us to chain callback and deal with errors. In Node.js extending the runtime allows code to appear synchronous and so becomes easier to understand.

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#441
  1. A synchronous function is having one function on execution but waiting for a response, then the next function can not be execute until the first is completed. Asynchronous functions allows to put the first function aside, and keep executing following codes.
  2. In a relatively simple operations can require three nested functions, when you have more complex operations it produces even more levels and sub-levels what is called the callback hell.
  3. A common use technique is promises. A Jquery promises library can be use to chain callbacks and deal with errors.
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