2020-04-16
3559
#vanilla javascript
Alexander Nnakwue
16959
Apr 16, 2020 ⋅ 12 min read

The evolution of asynchronous programming in JavaScript

Alexander Nnakwue Software engineer. React, Node.js, Python, and other developer tools and libraries.

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4 Replies to "The evolution of asynchronous programming in JavaScript"

  1. It’s mostly a good article, but please be rigorous and accurate, or you’ll confuse a lot of people.

    It’s untrue that function A doesn’t run inside function B. It does run, and a console.log() on the first line of A will prove that. Function A creates an anonymous function (the callback) and the body of the anonymous function is what doesn’t run until after B exits.

  2. Fyi the most important callback is the one fed directly into the asynchronous command offered by nodejs or the browser.

    For example, the “someFunction” in fs.readFile(url, someFunction). readFile is an asynchronous function (you’d just have to look it up or play with it to know that). It reads a file, then calls someFunction when it’s done.

    If it didn’t, none of this other stuff would matter. Most of this article is about clever ways to put what you desire into that “someFunction.” Including promises.

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