• RagingToad@feddit.nl
      51·
      2 years ago

      I’m not sure if you really want to know, but:

      greater than, smaller than, will cast the type so it will be 0>0 which is false, ofcourse. 0>=0 is true.

      Now == will first compare types, they are different types so it’s false.

      Also I’m a JavaScript Dev and if I ever see someone I work with use these kind of hacks I’m never working together with them again unless they apologize a lot and wash their dirty typing hands with… acid? :-)

      edit: as several people already pointed out, my answer is not accurate. The real solution was mentioned by mycus

      • hstde@lemmy.fmhy.ml
        2·
        2 years ago

        Not a JavaScript dev here, but I work with it. Doesn’t “==” do type coercion, though? Isn’t that why “===” exists?

        As far as I know the operators “>=” and “<=” are implemented as the negation of “<” and “>” respectively. Why: because when you are working with sticky ordered sets, like natural numbers, those operators work.

        Thus “0<=0” -> “!(0>0)” -> “!(false)” -> “true”

        Correct me if my thinking is wrong though.

      • TwilightKiddy
        1·
        2 years ago

        parseInt() takes string as an input. From first character, it goes on till it hits a non-digit character, and then converts resulting string to an integer. JS is not strictly-typed, so, when I feed it a floating point number, it implicitly converts it to string. Things like 0.01 it converts like "0.01", no problem here, our first character is zero, and then there is a dot, that’s not a digit, so we parse "0" to integer and get our zero. But at some point it switches to scientific notation when converting to string, so, our 0.0000001 becomes "1E-7". Then we take one as our first character, stop at E as it’s not a digit and we get "1" parsed to one. Praise the loosly-typed hell.

  • sheetmulch@kbin.social
    2·
    2 years ago

    I had a fun bug where unit tests started failing on an upgrade. Turns out someone was returning undefined from a comparator. Wtf, people.

  • PlexSheep@feddit.de
    1·
    2 years ago

    I wrote an exam about this stuff yesterday.

    In J’s equality is usually checked in a way that variables are casted to the type of the other one. “25” == 25 evaluates to truey because the string converted to int is equal to the int and the other way around.

    You can however check if the thing is identical, using “25” == 25 which skips type conversion and would evaluate as false.

    I assume the same thing happens here, null is casted to int, which gets the value 0.

  • Björn Tantau@feddit.de
    0·
    2 years ago

    Can someone explain this? I mean, the last result. Usually I can at least understand Javascript’s or PHP’s quirks. But this time I’m stumped.

  • Mars@beehaw.org
    0·
    2 years ago

    I know it’s a joke, but it’s an old one and it doesn’t make a lot of sense in this day and age.

    Why are you comparing null to numbers? Shouldn’t you be assuring your values are valid first? Why are you using the “cast everything to the type you see fit and compare” operator?

    Other languages would simply fail. Once more JavaScript greatest sin is not throwing an exception when you ask it to do things that don’t make sense.

    • OsrsNeedsF2P@lemmy.mlOP
      1·
      2 years ago

      Shouldn’t you be assuring your values are valid first?

      Step 1: Get to prod

      Step 2-10: Add features

      Step 11: Sell the company before it bites you