Apr 15, 2025
I gave a lightning talk at NebraskaJS about the complex, decades-long relationship between JavaScript and Java’s Date APIs:
The first half was a bit of a troll; I used a Java REPL (anonymized to look like Node) to demonstrate some of the more famously unexpected behavior in the Date class:
var date = new Date("March 20 2025");
date.getMonth(); // returns 2
date.getDay(); // returns 3
date.getYear(); // returns 125??
This code is syntactically correct Java and JavaScript, and behaves identically in both languages. One of the gifts of being told to “make it like Java” when adding dates to a ten-day-old language.
Java, of course, got markedly improved…
Apr 15, 2025
I gave a lightning talk at NebraskaJS about the complex, decades-long relationship between JavaScript and Java’s Date APIs:
The first half was a bit of a troll; I used a Java REPL (anonymized to look like Node) to demonstrate some of the more famously unexpected behavior in the Date class:
var date = new Date("March 20 2025");
date.getMonth(); // returns 2
date.getDay(); // returns 3
date.getYear(); // returns 125??
This code is syntactically correct Java and JavaScript, and behaves identically in both languages. One of the gifts of being told to “make it like Java” when adding dates to a ten-day-old language.
Java, of course, got markedly improved Date/Time APIs in version 8. Spearheaded by the lead developer of the de facto third-party date/time library, the java.time APIs were a breath of fresh air, and the new standard tool for all time-related matters.
JavaScript has been following the same path, with Maggie Pint (one of the maintainers of Moment.js) working to standardize the Temporal API. It’s been a long journey, with it reaching Stage 3 of the TC39 process way back in 2021, but hasn’t made its way to a browser engine just yet.
But it’s finally making its way into browsers! Safari, Firefox, and Deno have it in preview release, with Chromium browsers in active development.
So it’s a great time to refamiliarize yourself with the API, start checking out the polyfill, and start building fun stuff, like my gravel racing time estimator.