Ternary Operator in JavaScript With Multiple Expressions?

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再見小時候
再見小時候 2021-01-17 14:29
the_styles ? the_styles.appendTo(\'head\'); the_styles=null : the_styles = $(\'.stylesheet\').detach();

Obviously, this isn\'t valid. Notice the \"

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  • 2021-01-17 14:46

    Who needs the ternary operator?

    ​the_styles = !the_styles && $('.stylesheet').detach()​​​​ ||
                 the_styles.appendTo('head') && null;​
    

    Had to switch the expressions around as otherwise the null value of the first expression will always force the second expression .detach() to be evaluated.

    The only thing about clever code is that once you come back to it after a coffee break, it won't make any sense even to you. So this is much better:

    if(the_styles) {
        the_styles.appendTo('head')
        the_styles = null;
    }
    else {
        the_styles = the_styles.detach('.stylesheet');
    }
    

    To me, even the above simplistic version doesn't make any sense. The what part is obvious, but why is it doing that?

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  • 2021-01-17 14:51

    i agree with glowcoder but if you still want it:

    the_styles ? function(){ the_styles.appendTo('head'); the_styles=null;}() : the_styles = $('.stylesheet').detach();
    
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  • 2021-01-17 14:52
    the_styles ? (function() {the_styles.appendTo('head'); the_styles=null})() : <etc>
    

    Just wrap the code block in (function() { and })().

    Now for the hard part: why would you want to do this? Perhaps there's a better solution!

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  • 2021-01-17 14:53
    the_styles=the_styles || $('.stylesheet').detach(); the_styles.appendTo('head');
    
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  • 2021-01-17 14:59

    Use the comma operator this way:

    the_styles ? (the_styles.appendTo('head'), the_styles=null) : the_styles =  $('.stylesheet').detach();
    

    Here's what the Mozilla Developer Center writes about the comma operator:

    You can use the comma operator when you want to include multiple expressions in a location that requires a single expression. The most common usage of this operator is to supply multiple parameters in a for loop.

    Read more here: https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Operators/Special_Operators/Comma_Operator

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  • 2021-01-17 14:59
    the_styles ? the_styles.appendTo('head') : the_styles = $('.stylesheet').detach();
    

    you dont need to null it if your overwriting it !

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