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Instructor: The first technique we'll discuss

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is the Async Operations.

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The basic premise of Async Operations

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is that the code should not wait

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for long operations to complete, but instead

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the code begins a long operation and continues on

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and when the operation is done, then the code can continue

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from the point where the operation completed.

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Now, this is relevant mainly for IO operations

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such as operations related

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to files, to database access, to networking, et cetera.

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So if you have an operation that requires reading

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dozens of files, then using the Async Operation

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you can instruct the code to begin the reading operation.

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Meanwhile, continuing performing other operations

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and when the file reading is complete

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you can continue straight from the point

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in the code where the reading is done.

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Now, almost every development platforms

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supports this concept nowadays, and let's see an example.

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And what you see here is an implementation

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of the Async await pattern in node.js.

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There are two things to know in this code.

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First is the a wait keyword

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which signals the code to begin this operations

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the fetch operation, which is a long operation.

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And while the code is fetching the data

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from this address, then the calling method

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can continue doing whatever they did before.

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Now for this to happen, there is also the Async keyword.

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So the Async keyword, signals the calling method

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that this function, the Async Ajax await function

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is an Async function,

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which means it might have an await Q ordinate

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so the calling function might continue do something

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after calling the Async Ajax await.

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And again, the I Async await pattern exists

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in almost every development platform.

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This pattern is a very powerful one

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and you should always aspire to use it.

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It frees the threads on the web server

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and it dramatically improves the performance of the API.