Asynchronous Programming - Reading Assignment

Javascript Programming
#762

1. What is the difference between synchronous and asynchronous functions?
Synchronous functions are executed in a sequence, each statement waits for the previous to finish before executing. Asynchronous functions don’t have to wait, they can be startet and put aside – the program can continue to run. That keeps a site or app responsive, reducing waiting time for the user.

2. What is callback hell?
Complex operation in a Javascript code, where the program tries to execute multiple asynchronous operations one after the other. That will produce several callbacks in various levels and sublevels which will easily end up in error prone, hard to read and hard to maintain code. For example when you have a callback that is nested in another callback which is nested in yet another callback…

3. Which technique can help us solve callback hell?
Promises. A ’promise’ is an object that will return a value in future. Because of this “in future” thing, Promises are well suited for asynchronous JavaScript operations. What also helps is to write comments, to split function s into smaller functions…

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#763

  1. Synchronous means that in a single threaded environment, only one section of code can be running at any one time.
    Asynchronous means tasks can be initiated, and then put aside until a later date while our code is doing something else in the meantime. And when that task gets a response, then it will light up and do its thing.

  2. Code that has several nested functions within it, these complex operations tend to produce more levels and sub levels; this is called callback hell.

  3. A common pattern to deal with callback hell is to use promises. JQuery ships with a simple built in promise library that enables users to chain callbacks and deal with errors.

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#764

What is the difference between synchronous and asynchronous functions?
While synchronous functions only allow us to make one task at a time, asynchronous functions can “wait” in the background, being only triggered when they receive a response from an outiside server or another input from the user.

What is callback hell?
Callback hell is when we have functions inside functions, so each function need an answer from another function being all interlinked - like a chain - bottom to top.

Which technique can help us solve callback hell?
One ways is to use promises, in where we use different libraries and we make the callbacks between them. This way is easier to test each function separately and check for eventual errors. Other way is to use timeouts, if we give time for each function to execute and have an answer back we avoid callback hell, and we can check for errors in every step.

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#765
  1. Synchronous functions execute one at a time and in order, the function must complete before the next one can be computed.
    Asynchronous functions can be ran simultaneously and do not need to complete before other functions are ran. you can return to continue/ complete the function at a later time.
  2. When there are multiple levels and sub levels of call back functions this is known as callback hell.
  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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#766

  1. Synchronous functions are blocking while asynchronous functions are not. In synchronous functions, statements complete before the next statement is run.

  2. This is a big issue caused by coding with complex nested callbacks

  3. Promises

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#767
  1. synchronous functions are blocking while asynchronous functions are non-blocking. Blocking means, that the programm is waiting for the function to finish while it is blocking the whole program.
  2. callback hell is the term that is used for code with many nested (callback) functions. It usually gets very hard to understand what the code does.
  3. Promises can help us
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#768

In programming , synchronous operations block instructions until the task is completed, while asynchronous operations can execute without blocking other operations.

Callback hell is a phenomenon that afflicts a JavaScript developer when he tries to execute multiple asynchronous operations one after the other. By nesting callbacks in such a way, we easily end up with error-prone, hard to read, and hard to maintain code.Soln: Best code practice to handle it

Write comments.
Split functions into smaller functions.
Using Promises.
Using Async/await.
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#769
  1. the difference between synchronous and asynchronous functions is that synchronous functions can only run one by one, each after another, whereas asynchronous functions can run simultaneously.
  2. A callback hell is a situation when multiple interconnected callbacks pile up waiting for that one callback in order to continue with the code.
  3. Promises
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#770

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

Synchronous functions can block any additional functions from running until they finish running. While asynchronous functions can be set aside, while they await a response.

2). What is callback hell?

Having a series of nested functions which rely on each other to complete a particular task.

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

Promise in jQuery helps us chain callback hell and deal with errors as well.

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#771
  1. Synchronous functions operate one at a time and stop all other executions until they are done. Asynchronous functions execute in concurrence with other functions and don’t need to wait for other functions to finish execution before they can go on ahead with what they’re doing.
  2. Callback hell is the complex structure, with multiple levels of nested functions, that asynchronous functions can have in contexts of a certain complexity.
  3. Promises, which allow us to chain callbacks and handle errors.
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#772
  1. Synchronous functions block the program’s further execution until it has finished the task. Asynchronous functions are put aside until the program does another task.
  2. Nested functions. They allow us to create asynchronous code, but the code can become messy, hard to read.
    3.Promises.
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#773
  1. What is the difference between synchronous and asynchronous functions?
    Synchronous functions run single treaded i.e. one at a time, and need the whole sequence to run before it can end.
    Asynchronous functions can run operations simultaneously and put certain operations aside while it waits for a reply.
  2. What is callback hell? nested functions - each relying on the upper lower level to complete tasks.
  3. Which technique can help us solve callback hell? JS has a system called promises jQuery ships with a simple built-in promise library that enables us to chain callbacks and deal with errors.
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#774

  1. Synchronous functions are functions that happen one at a time. Asynchronous functions are functions that work simultaneously, and if one function is loading, it will move on to the next function until the loading function is loaded.

  2. “Complex operations tend to produce even more levels and sub-levels, which is what is poetically known as callback hell.”

  3. Coders use Promises to get out of callback hell.

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#775

  1. Synchronous functions only executes code one at a time. Asynchronous functions can be initiated and then put aside to start another task.

  2. Callback hell is when you have callbacks within callbacks within callbacks. It makes the code hard to read.

  3. You can use promises.

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#776
  1. Synchronous functions demand the full attention of the browser and cannot stop until the function has completed. Asynchronous functions can be set aside to be fully run later on, asynchronous functions don’t need to be fully completed after you start them, so that the browser can move on to it’s next task(s).
  2. Callback hell is when you have multiple nested functions within a complex operation.
  3. We can use promises to solve callback hell.
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#777
  1. In Synchronous Function, the tasks are single threaded, it can perform only one task at time. In Asynchronous Function, a task can be initiated and then put aside until a later data while Javes get started on the next task on his to do list.
  2. Callback hell happens when complex operations produce more levels and sub-levels of many asynchronous operations.
  3. One technique to be applied to solve callback hell is to extend runtime, so the asynchronous code can be abstracted away and write code that “appears” synchronous.
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#778
  1. What is the difference between synchronous and asynchronous functions? Synchronous functions occur one at a time and block the program execution until it has finished. Asynchronous functions allow subsequent functions to begin before it has completed all of its tasks
  2. What is callback hell? A situation where several nested callback functions are needed to perform a simple task
  3. Which technique can help us solve callback hell? Promises can be used to write asynchronous code that appears as though it is executing in a top-down way. jQuery and AngularJS come with promise library
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#779
  1. Synchronous functions are completed one single function at a time before the next function is executed whereas asynchronous functions can be “call back” to run a second function before the first one has been completed.
  2. Callback hell is where a relatively simple operation may require several levels of nested functions.
  3. Promises is a build in promise library to deal with callback hell.
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#780

  1. What is the difference between synchronous and asynchronous functions?
    Synchronous functions can cause delays/slowdowns on the webpage as they must execute in order - i.e. - first one must finish before the second can begin in a single-threaded code environment. Asynchronous functions (multi-threaded) allow for concurrent execution (or seeming concurrence) by nesting functions - i.e. - while waiting for a callback from one function, the second function is running/completing.

  2. What is callback hell?
    “Callback Hell” is created when there are so many levels and sub-levels of nested functions waiting for “callbacks” (i.e. - completion of nested-function execution responses) that the complexity creates issues.

  3. Which technique can help us solve callback hell?
    On the client side (browser), we can use the jQuery promise library to chain callbacks and deal with errors. In Node.js (server side ) we can write code that appears synchronous by abstracting away the asynchronous code (rewriting asynchronous code to give us synchronous flow control, using Meteor Fibers, which can run on both the client and server.

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#781

1. What is the difference between synchronous and asynchronous functions?
JavaScript is considered to be single-threaded, such that only one task at time can be handled. In this kind of environment only one single section of code at time can be running. In such case we talk about synchronicity. This mean that even making API’s call, a synchronous function would perform the call and waiting until the response is received, locking the execution of rest of the code. With asynchronous function, on the other hand, task can be initiated and then put aside. This allows to compute different actions without locking the code with pending action.

2. What is callback hell?
A callback hell happen when a code has a lot of nested functions, when one function callback another function and so on. This type of situation make harder to understand the code an maintain it.

3. Which technique can help us solve callback hell?
A typical way to solve this problem is using “promises”. JQuery help us to handle this kind of issue enabling to chain callbacks and deal with errors. Another way to handle this problem is using Node.js that extend the runtime an make asynchronicity looks like synchronicity.

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