PHP不会打印分配了布尔值的变量

如何解决PHP不会打印分配了布尔值的变量

我有一些PHP代码，应该检查是否在$ _GET全局变量中分配了某个值。如果不是，它将自动放入一个预定值。如果存在，则应打印$ _GET值的值：

<?PHP
            if(!isset($spaceObjects)){$spaceObjects = 0;}else{$spaceObjects = $_GET['spaceObjects'] == true;}
            if(!isset($numOfStars)){$numOfStars = 100;}else{$numOfStars = intal($_GET['numOfStars']);}
            if(!isset($startwinkles)){$startwinkles = 0;}else{$startwinkles = ($_GET ['starTwinkles'] == true);}
            if(!isset($numOfMeteorsMax)){$numOfMeteorsMax = 8;}else{$numOfMeteorsMax = intval($_GET['numOfMeteorsMax']);}
            if(!isset($twinklePausing)){$twinklePausing = 1;}else{$twinklePausing = ($_GET['twinklePausing'] == true);}
            if(!isset($nightCycle)){$nightCycle = 0;}else{$nightCycle = ($_GET['nightCycle'] == true);}
            if(!isset($music)){$music = 1;}else{$music = ($_GET['musicEnabled'] == true);}
            if(!isset($nightSounds)){$nightSounds = 0;}else{$nightSounds = ($_GET['nightSounds'] == true);}
            if(!isset($nightSoundsVol)){$nightSoundsVol = 0.1;}else{$nightSoundsVol = intval($GET['nightSoundsVol']);}
            ?>
            let controlVariables = {
                spaceObjects: <?PHP echo $spaceObjects;?>,numOfStars: <?PHP echo $numOfStars;?>,starTwinkles: <?PHP echo $startwinkles;?>,numOfMeteorsMax: <?PHP echo $numOfMeteorsMax;?>,disableTwinklingWhileSpaceObjectGenerated: <?PHP echo $twinklePausing;?>,nightCycle: <?PHP echo $nightCycle;?>,music: <?PHP echo $music;?>,nightSounds: <?PHP echo $nightSounds;?>,nightSoundsVol: <?PHP echo $nightSoundsVol;?>
            };

（请注意，这是javascript，而PHP在标记内）。 当我运行它时，它什么也不输出。我试图寻找答案，但一无所获。我做错了什么？

解决方法

尝试用条件替换echo以输出特定文本而不是变量本身。 当为true时，返回的布尔输出为1，而如果变量为false，则无输出。 例如：

let controlVariables = {
    spaceObjects: <?php echo ($spaceObjects)? 'true' : 'false';?>,...
}