• kevincox@lemmy.ml
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    9 months ago

    JS’s == has some gotchas and you almost never want to use it. So === is what == should have been.

    All examples are true:

    "1" == true
    [1, 2] == "1,2" 
    " " == false
    null == undefined 
    

    It isn’t that insane. But some invariants that you may expect don’t hold.

    "" == 0
    "0" == 0
    "" != "0" 
    
    • Feathercrown@lemmy.world
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      9 months ago

      One neat feature is you can compare to both null and undefined at the same time, without other falsey values giving false positives. Although that’s not necessary as often now that we have nullish coalescing and optional chaining.

      • kevincox@lemmy.ml
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        9 months ago

        I just tested and Terser will convert v === null || v === undefined to null==v. Personally I would prefer to read the code that explicitly shows that it is checking for both and let my minifier/optimizer worry about generating compact code.