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humanwhocodes

Introducing Env: A better way to read environment variables in JavaScript

Feb 16, 20219 min read

This post originally appeared on the Human Who Codes blog on February 16, 2021. If you write server-side JavaScript, chances are you've need to read information from environment variables. It's considered a best practice to share sensitive informatio...

Creating a JavaScript promise from scratch, part 7: Unhandled promise rejections

Jan 19, 202129 min read

This post originally appeared on the Human Who Codes blog on January 19, 2021. When promises were introduced in ECMAScript 2015, they had an interesting flaw: if a promise didn't have a rejection handler and was later rejected, you would have no idea...

Creating a JavaScript promise from scratch, Part 6: Promise.all() and Promise.allSettled()

Dec 16, 202017 min read

This post originally appeared on the Human Who Codes blog on December 16, 2020. In my last post, I walked you through the creation of the Promice.race() and Promise.any() methods, both of which work on multiple promises and return a single promise th...

Creating a JavaScript promise from scratch, Part 4: Promise.resolve() and Promise.reject()

Oct 13, 20208 min read

This post originally appeared on the Human Who Codes blog on October 13, 2020. When you create a promise with the Promise constructor, you're creating an unsettled promise, meaning the promise state is pending until either the resolve or reject funct...

Creating a JavaScript promise from scratch, Part 3: then(), catch(), and finally()

Oct 6, 202030 min read

This post originally appeared on the Human Who Codes blog on October 6, 2020. In my first post of this series, I explained how the Promise constructor works by recreating it as the Pledge constructor. In the second post in this series, I explained ho...

Creating a JavaScript promise from scratch, Part 2: Resolving to a promise

Sep 29, 20209 min read

This post originally appeared on the Human Who Codes blog on September 29, 2020. In my first post of this series, I explained how the Promise constructor works by recreating it as the Pledge constructor. I noted in that post that there is nothing asy...