Asynchronous Programming - Reading Assignment

Javascript Programming
#902
  1. Asynchronous functions are tasks that can be initiated and then placed to the side until a later date while it gets started on the next tasks. A synchronous task is when it continuously runs until its completed then moves on to the next task.
  2. A callback is a second argument, also called the event handler and it responds to a special event called the ajaxDone that’s fired by thee browser.
  3. A common way do deal with callbacks that are excessive is to use promises.
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#903

  1. What is the difference between synchronous and asynchronous functions?
    Synchronous functions can only handle one task at a time, while asynchronous functions also handle one task at a time, they can disconnect from it and revisit the task at a later time.

  2. What is callback hell?
    It is when functions have many levels and sub level operations, and it get’s too much to deal with and handle.

  3. Which technique can help us solve callback hell?
    In Node.js you can extend the runtime, so this removes the asynchronicity and makes the code looks synchronous.

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#904

  1. What is the difference between synchronous and asynchronous functions?
    Javascript can only execute one task at a time. Synchronous functions will finish executing before moving on. Asynchronous functions can be initiated and then put aside while other functions run.

  2. What is callback hell?
    Lots of nested functions which render the code difficult to read.

  3. Which technique can help us solve callback hell?
    Promises, which allow us to chain callbacks and deal with errors.

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#905

  1. What is the difference between synchronous and asynchronous functions?
    Synchronous functions are functions that execute in sequence after each other. Asynchronous functions have characteristics that may make their execution occur outside of the code sequence.

  2. What is callback hell?
    Callback hell is when the code has excessive amounts of callbacks where they become error-prone and hard to read.

  3. Which technique can help us solve callback hell?
    Promises

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#906

1.What is the difference between synchronous and asynchronous function?
Synchronous function works in a single-threatened environment where each section of the code is executed task by task, E.g. the second task won’t run until the first is completed.

Asynchronous function works differently, they don’t process each section step by step.
If one section of code is not completed, the asynchronous function is able to go further to an other task.

2.What is callback hell?
Callbeck hell is a collection of messy code of synchronous callback functions which are difficult to maintain.

3.Which technique can help us solve callback hell?
The Promises technique.

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#907

  1. A synchronous functions style is blocking and will only handle one task at a time until complete.
    asynchronous functions will not block and can be initiated and then put aside until a later date.

  2. Callback hell is for example three levels of nested functions producing extended levels and sub-levels of code which is difficult to manage.

  3. A technique to deal with call back hell is to use promises which enables the devloper to chain callback and deal with bugs and errors.

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#908

  1. What is the difference between synchronous and asynchronous functions?
    Synchronous functions are functions that run one task at a time.

    Asynchronous functions allow JS to run different tasks in parallel.

  2. What is callback hell?
    A callback is a function passed as an argument to another function.

    Setting up multiple nested callback functions are sometimes necessary to do complex tasks, which in turn produces levels and sub-levels of code. This is what’s referred to as callback hell.

  3. Which technique can help us solve callback hell?
    We can use Promises. A promise represents the result of an asynchronous operation.

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#909
  1. What is the difference between synchronous and asynchronous functions?
    Synchronous functions - Only one section of the code in the function can run at any one time.
    Asynchronous functions - More than one section of the code in the function can run at any one time.*
  2. What is callback hell?
    Arguments in an argument in an argument…
  3. Which technique can help us solve callback hell?
    the use of promises , which enables us to chain callbacks and deal with errors.
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#910

What is the difference between synchronous and asynchronous functions?

In synchronous operations tasks are performed one at a time. You need to wait for a task to finish before moving onto the next one.

In asynchronous operations, on the other hand, you can move to another task before the previous one finishes. This way, with asynchronous programming you’re able to deal with multiple requests simultaneously , thus completing more tasks in a much shorter period of time.

What is callback hell?

Callbacks are nothing but functions that take some time to produce a result. As these take time to finish, we can neither proceed to next line because it might throw an error saying unavailable nor we can pause our program. So we need to store the result and call back when it is complete.

This is a big issue caused by coding with complex nested callbacks. Here, each and every callback takes an argument that is a result of the previous callbacks. In this manner, the code structure looks like a pyramid, making it difficult to read and maintain. Also, if there is an error in one function, then all other functions get affected.

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.

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#911
  1. What is the difference between synchronous and asynchronous functions?

A synchronous task will occupy Javes continuously until its completion. An asynchronous task can be initiated and then put aside until a later date while our valet gets started on the next task on his to-do list.

  1. What is callback hell?

Callback hell is when more complex operation tends to produce even more levels and sub-levels.

  1. Which technique can help us solve callback hell?

“Promises” is a common patterns used to deal with excessive callbacks.

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#912
  1. The difference is how they complete the task. the first one do one task and only after the end do another one, whereas asynchronous, if the task requires much time, they don’t wait the response and start the next one in the meanwhile.
  2. It is when the computer have to wait a lot of response from a lot of functions
  3. Using ‘promises’ in jQuery enables us to chain callback and deal with errors. In Node.js, you can abstract asynchronicity to extend runtime and build a synchronous equivalent function.
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#913

  1. Synchronous functions are executed sequentially with Javascript waiting for their completion before moving on to the next task. Asynchornous functions allow the program to continue through it’s loop while it waits for a function to complete.

  2. Callback hell is where increasingly complex programs create increasing amounts of callbacks.

  3. In jQuery promises are used. Other libraries have their own solutions.

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#914
  1. What is the difference between synchronous and asynchronous functions?
    • Synchro
      • Single-threaded
        • Only one section of code can run at any one time
    • Asynchro
      • Code put aside to run when called to do so, ie to-do list
        • This ‘to-do’ list is called the event loop
        • JS engine actually sports an additional background thread which manages event loops
        • Code takes the form of Ajax
          • Commonly used through jQuery wrapper
  2. What is callback hell?
    • Nested functions can take on may levels especially in complex operations
      • This can lead to multiple callbacks
        • Therefore callback hell
  3. Which technique can help us solve callback hell?
    • Use promises
      • jQuery ships with simple built in promise library, enabling for chain callbacks
    • Node.js
      • Extend runtime and abstract away asynchronicity
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#915

Asynchronous Programming

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

JavaScript is single threaded meaning it can only execute one function at a time. A synchronous function must be completed once called whereas an Asynchronous function can be ‘set aside’ and completed later.

Asynchronous code usually goes through Ajax or jQuery.

  1. What is callback hell?

Callback hell is when there are too many levels or sublevels to the code making it confusing.

  1. Which technique can help us solve callback hell?

We can use promises with JQuery built-in promise library. This lets us chain callbacks and deal with errors.

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#916

What is the difference between synchronous and asynchronous functions?

  • Mainly, a synchronous function needs to be completed before other functions are executed afterwards while an asynchronous function, when called, one can move to another task before the previous one finishes.

What is callback hell?

  • Multiple levels of nested asynchronous functions to perform one operation

Which technique can help us solve callback hell?

  • Use of promises
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#917
  1. Synchronous functions will execute until they are complete. Asynchronous functions will be called and then put aside to allow for other tasks to be completed in the meantime.
  2. Callback hell is when you have an abundance of nested functions that are being used as callbacks and things are getting overly hellish.
  3. jQuery built in promise library that lets us chain callbacks and deal with errors.
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#918

  1. Synchronous functions will operate until their job is finished. Asynchronous functions do not block the javascript thread and the function can complete at a later point.

  2. callback hell is where several nested functions are needed in order for our code to perform.

  3. You can use the simple Jquery Promises library OR you can use the fibers package in node.js to write our code in synchronous style.

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#919
  1. What is the difference between synchronous and asynchronous functions?
    Syncronous functions us e thread and can only perform one task at a time. Asyncronous functions do not have this limitiation.
  2. What is callback hell?
    it means that complex tasks require several nested functions to perform which can lead to many differnet levels inside a single task.
  3. Which technique can help us solve callback hell?
    We can uses so called promises provided by a library.
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#920

  1. synchronous functions block the script from continuing to do anything else whereas asynchronous functions schedule events to be handled later so that a script can continue running

  2. callback hell is the resulting stack of function calls that need resolution when you’ve nested too many functions inside each other, (i imagine) causing dependencies that are hard to trace when debugging becomes necessary…

  3. to resolve this issue, apparently jquery uses “promises”, which i imagine to save errors/codes to be logged at some point and fill out bare minimum info to functions awaiting input in the call stack…? …node.js apparently uses some fancy behind the scenes tool called Fibers to allow one to write code without having to worry about making it asynchronous

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#921
  1. Synchronous functions are when only one fucntion can be completed at a time, and it wont move to the second function until the first one has been complete. Asynchronous functions allow the program to keep carrying out the next functions, even if one isnt complete, and will call back on the incomplete one when it is able to

2 Callback hell is when you have too many nested functions which are all waiting on callbacks for the next set of nested functions, which are waiting on callbacks from the next set etc etc

  1. using promises can solve callback hell
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