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If you run this JavaScript function on the 31st of a month, the result will be a month off. The best part is that this is the intended behvaior. JavaScript is a cursed language. (lemmy.ml)
submitted 2 years ago by to c/programmerhumor@lemmy.ml
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function getMonthName(monthNumber) {
  const date = new Date();
  date.setMonth(monthNumber - 1);

  return date.toLocaleString([], { month: 'long' });
}

The current day of month will have an impact on the behavior of this method. Conceptually it will add the number of days given by the current day of the month to the 1st day of the new month specified as the parameter, to return the new date. For example, if the current value is 31st January 2016, calling setMonth with a value of 1 will return 2nd March 2016. This is because in 2016 February had 29 days.

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[–] 4 points 2 years ago (3 children)

I love js. But the date object has always been a total pain. Moment.js is a good package to deal with it, but yeah, it's currently deprecated, but it would be nice if it or something like it became part of ECMAScript.

I have no idea why it hasn't yet, except that it might be that js needs to work for everyone, not just the us. So time is not standard.

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  • [–] 3 points 2 years ago* (1 child)

    The date API is like the original rip of the Java date API. Barely changed, and totally backwards compatible nonsense.

    Temporal is the new JavaScript/ECMAScript date API.
    It's stage 3, and likely stable (just a few kinks being worked out). So you could polyfill it for production.
    https://github.com/tc39/proposal-temporal

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  • [–] 1 point 2 years ago

    Speaking of Java RipS. How annoying is it the JS has left Java in the dust as far as looser standards?

    Developing in Java: YOU FORGOT A SEMI-COLON ARE YOU CRAZY?! HOW IS THE COMPILER SUPPOSED TO KNOW WHAT TO DO?!

    Developing in JS: Who gives a fuck about semi-colons?

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