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The JavaScript APIs we have today are so much better than those we had even a decade ago. Consider the transition for XMLHttpRequest to fetch(): the developer experience is dramatically better, allowing us to write more succinct, functional code that accomplishes the same thing. The introduction of promises for asynchronous programming allowed this change, along with a series of other changes that

Open source sustainability is a topic that is just starting to get the attention that it deserves. So much of the technology sector is run on software that can be used for free without any further obligation. However, as companies profit from using this software for free, the maintainers of the software often struggle to find enough time to work on the software while making enough money to survive

Introducing Env: a better way to read environment variables in JavaScript Reading environment variables in JavaScript is fraught with peril. Env makes it better. 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 information, such as access tokens, inside of environment variables to keep th

Create TypeScript declarations from JavaScript and JSDoc Even if you don't write your code in TypeScript you can still generate .d.ts files to provide more information to developer tools. For a variety of reasons, I prefer to write my code in vanilla JavaScript with JSDoc comments rather than writing in TypeScript. Today’s smart code editors, like Visual Studio Code, are able to read type informat

GitHub Actions1 are programs designed to run inside of workflows2, triggered by specific events inside a GitHub repository. To date, people use GitHub Actions to do things like run continuous integration (CI) tests, publish releases, respond to issues, and more. Because the workflows are executed inside a fresh virtual machine that is deleted after the workflow completes, there isn’t much risk of

Why I've stopped exporting defaults from my JavaScript modules After years of fighting with default exports, I've changed my ways. Last week, I tweeted something that got quite a few surprising responses: In 2019, one of the things I’m going to do is stop exporting things as default from my CommonJS/ES6 modules. Importing a default export has grown to feel like a guessing game where I have a 50/50

Job Details The data alone doesn’t really tell the full story, so here are the details around each position. I’ve also included how I came to work at each company, as I think it’s important to recognize blind resume submissions from having contacts as a company. In 2006, I moved from Massachusetts to California. This undoubtedly affected my pay positively due to the higher cost of living in Califo

The ECMAScript 2016 change you probably don't know How the JavaScript strict mode directive changed in 2016. Compared to ECMAScript 6 (also known as ECMAScript 2015), ECMAScript 2016 was a minor update to the language specification for JavaScript. This was due to the decision that ECMAScript editions would now move to a yearly release cycle, effectively just a snapshot of all the features that wer

One of the most long-awaited features of ECMAScript 6 is the formal definition of modules as part of the language. For years, JavaScript developers have struggled with organizing their code and needing to decide between alternate ad-hoc module formats like RequireJS, AMD, and CommonJS. Formally defining modules as part of JavaScript will eliminate a lot of heartache in the future, but right now, t

With all of the new syntax in ECMAScript 6, you’re bound to periodically find something that is confusing (likely as you’re hunting down an error). Recently, I’ve seen an uptick in the reporting of a specific type of error as it relates to destructuring assignment[1] using object patterns. Destructuring basics Before you can understand the problem, it’s helpful to look at a few examples of destruc

Peter-Paul Koch recently wrote a blog post entitled, “Stop pushing the web forward” [1], in which he argued for a one-year moratorium on adding new features to the web platform. By new features, he means new APIs and capabilities in HTML, CSS, and JavaScript, arguing: We’re pushing the web forward to emulate native more and more, but we can’t out-native native. We are weighed down by the millstone

Posted at May 6, 2014 by Nicholas C. Zakas Tags: Browsers, Internet, URLs Last week, there was a fair bit of furor when Jake Archibald wrote an article1 describing an experimental feature in Chrome that hides all but the domain name of the URL you’re on. The idea is very similar to what already happens in the iOS 7 version of Safari: once navigation is underway, the URL is hidden and only the doma

I’ve recently been working on a project involving Google Spreadsheets. My goal was to store data in the spreadsheet using a form and then read the data from that spreadsheet using a Node.js application. Having no experience with Google web services, I ended up digging through a lot of documentation only to find that there are no official Node.js examples. So I pieced together the process of access

I’m very proud to announce that Principles of Object-Oriented JavaScript is now shipping! For frequent readers, this book is the print version of my self-published ebook, The Principles of Object-Oriented Programming in JavaScript, which I published at the beginning of 2013. Birth of an ebook The whole process began after a chat with Kate Matsudaira. We were talking about the ins and outs of publi

It was four months ago when I announced the start of the ESLint project. My initial goal was to create a fully-pluggable JavaScript code quality tool where\ every single rule was a plugin. Though I like and appreciate JSHint, the inability to be able to define my own rules alongside the existing ones was keeping several of my projects from moving forward. After doing an initial prototype using Esp

Posted at December 11, 2012 by Nicholas C. Zakas Tags: ECMAScript 5, JavaScript I was working with a client recently on a project that could make full use of ECMAScript 5 when I came across an interesting problem. The issue stemmed from the use of mixins, a very common pattern in JavaScript where one object is assigned properties (including methods) from another. Most mixin functions look somethin

Like it or not, ECMAScript 6 is going to have classes1. The concept of classes in JavaScript has always been polarizing. There are some who love the classless nature of JavaScript specifically because it is different than other languages. On the other hand, there are those who hate the classless nature of JavaScript because it’s different than other languages. One of the biggest mental hurdles peo

Earlier this week, Microsoft released TypeScript1, a new compile-to-JavaScript language for “application scale JavaScript.” My initial reaction was confusion: Um, why? blogs.msdn.com/b/somasegar/ar… (via @izs) — Nicholas C. Zakas (@slicknet) October 1, 2012 It seems like almost every week there’s a new language that’s trying to replace JavaScript on the web. Google received a lukewarm reception wh

I typically don’t get too excited when new open source JavaScript utilities are released. It may be the cynic in me, but generally I feel like there’s very little new under the sun that’s actually useful. Most of these utilities are knockoffs of other ones or are too large to be practically useful. When I first came across XAuth, though, a little tingly feeling of excitement swept over me. And the

This is a problem I’ve come across frequently, and since it has come up again recently, I thought I’d explore this issue in the hope that it will save others some trouble. There are so many problems that this one issue can lead to that it’s baffling browsers still behave this way. The issue? An HTML image, either via <img> tag or JavaScript Image object, that has its src set to “” (an empty string

A couple of years ago, web developers were banging their head against the first wall in Ajax: the same-origin policy. While we marveled at the giant step forward enabled by cross-browser support for the XMLHttpRequest object, we quickly bemoaned the fact that there was no way to make a request to a different domain from JavaScript. Everyone setup proxies on their web sites, which was the onset of

In a previous post, I talked about Internet Explorer 8′s wide array of browser and document modes. Most people are pretty familiar with how the various document modes affect layout in terms of how CSS is implemented, but what has been lost is how the document mode affects the core JavaScript engine in the browser. These changes are somewhat subtle, but important to understand when you’re working w

In this new Web 2.0, mashup world that the Internet has become, a lot of focus has been placed on the use of iframes for embedding third-party content onto a page. Iframes provide a level of security since JavaScript access it limited by domain name, so an iframe containing content from another site cannot access JavaScript on the containing page. This cross-domain restriction goes both ways as th

HTTP cookies, most often just called “cookies,” have been around for a while but are still not very well understood. The first problem is a lot of misconceptions, ranging from cookies as spyware or viruses to just plain ignorance over how they work. The second problem is a lack of consistent interfaces to work with cookies. Despite all of the issues surrounding them, cookies are such an important

Posted at January 27, 2009 by Nicholas C. Zakas Tags: Iteration, JavaScript, Memoization, Performance, Recursion Recursion is the enemy of fast-running scripts. Too much recursion can cause the browser to grind to a halt or quit unexpectedly, and so must be addressed a serious performance problem in JavaScript. In part 2 of this series, I wrote briefly about handling too much recursion in a functi

Last week, I covered the first reason why JavaScript can take too long to execute: too much happening in a loop. There’s a similar problem with functions in that sometimes they’re just doing too much. Usually this means there’s too many loops (as opposed to too much happening in a loop), too much recursion, or simply too many different operations being performed. Too many loops are often caused by