• frezik@midwest.social
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    7 months ago

    I’d say this example doesn’t fully show off what immutable data can do–it tends to help as things scale up to much larger code–but here’s how I might do it in JS.

    function generate_class_name( display_type, size, bordered, class_name_prop ) 
    {
      classes = [
          'btn',
          ( display_type ? display_type : [] ),
          ( size ? size : [] ),
          ( bordered ? bordered : [] ),
          ( class_name_prop ? class_name_prop : [] ),
      ];
    
      return classes.flat().join( " " );
    }
    
    console.log( "<"
        + generate_class_name( "mobile", "big", null, null )
        + ">" );
    console.log( "<"
        + generate_class_name( "desktop", "small", "solid", "my-class" ) 
        + ">" );
    console.log( "<"
        + generate_class_name( null, "medium", null, null ) 
        + ">" );
    

    Results:

    <btn mobile big>
    <btn desktop small solid my-class>
    <btn medium>
    

    Notice that JavaScript has a bit of the immutability idea built in here. The Array.flat() returns a new array with flattened elements. That means we can chain the call to Array.join( " " ). The classes array is never modified, and we could keep using it as it was. Unfortunately, JavaScript doesn’t always do that; push() and pop() modify the array in place.

    This particular example would show off its power a little more if there wasn’t that initial btn class always there. Then you would end up with a leading space in your example, but handling it as an array this way avoids the problem.

    • madcaesar@lemmy.world
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      7 months ago

      Very interesting. Actually the part you mention about there being an initial 'btn' class is a good point. Using arrays and joining would be nice for that. I wish more people would chime in. Because between our two examples, I think mine is more readable. But yours would probably scale better. I also wonder about the performance implications of creating arrays. But that might be negligible.