意外 "Illegal return statement"

Question

所以我有我的代码：

var canvas = document.getElementById('c');
var ctx = c.getContext('2d');
var player = {
 x: 0,
 y: 0,
 width: 20,
 height: 20,
 speed: 3,
 velX: 0,
 velY: 0,
 jumping: false,
 grounded: false,
 gravity: 0.35,
 friction: 0,
 glitchCooldown: 0,
 keys: []
};
var walls = [];
walls.push({
 x: 50,
 y: 230,
 width: 20,
 height: 20
})
walls.push({
 x: 150,
 y: 230,
 width: 20,
 height: 20
})
player.y = canvas.height - player.width;
document.body.addEventListener("keydown", function(e) {
    player.keys[e.keyCode] = true;
});
 
document.body.addEventListener("keyup", function(e) {
    player.keys[e.keyCode] = false;
});
function update() {
 if (player.keys[68]) {
  if (player.velX < player.speed) {
   player.velX++;
  }
 };
 if (player.keys[65]) {
  if (player.velX > -player.speed) {
           player.velX--;
       }
 };
 if (player.keys[87]) {
    if (!player.jumping) {
     player.jumping = true;
     player.grounded = false;
     player.velY = -player.speed*2;
    }
 };
 if (player.keys[74]) {
  glitch('backward');
 };
 if (player.keys[75]) {
  glitch('down')
 };
 if (player.keys[76]) {
  glitch('forward')
 };
 player.velY += player.gravity;
 player.velX *= player.friction;
 player.x += player.velX;
 player.y += player.velY;
 ctx.clearRect(0, 0, canvas.width, canvas.height);
 player.grounded = false;
 for (var i = 0; i < walls.length; i++) {
        rect('black', walls[i].x, walls[i].y, walls[i].width, walls[i].height);
        var dir = colCheck(player, walls[i]);
        if (dir === "l" || dir === "r") {
      player.velX = 0;
      player.jumping = false;
   } else if (dir === "b") {
      player.grounded = true;
       player.jumping = false;
   } else if (dir === "t") {
      player.velY *= -1;
   }
    }
    if (player.grounded){
     player.velY = 0;
 }
 if (player.glitchCooldown <= 0) {
  player.glitchCooldown = 0;
 }
 player.glitchCooldown--;
  rect('black', player.x, player.y, player.width, player.height);
 requestAnimationFrame(update);
};
requestAnimationFrame(update)
function rect(color, x, y, width, height) {
 ctx.fillStyle = color;
 ctx.fillRect(x, y, width, height);
}
function glitch(x) { 
  if (player.glitchCooldown <= 0) {
  setTimeout(function(){player.width = 0}, 200);
     setTimeout(function(){player.width = 20}, 220);
     setTimeout(function(){player.width = 0}, 400);
     setTimeout(function(){player.width = 20}, 420);
     setTimeout(function(){player.width = 0}, 500);
     setTimeout(function(){player.width = 20}, 510);
     setTimeout(function(){player.width = 0}, 530);
     setTimeout(function(){player.width = 20}, 550);
     if (x == 'forward'){setTimeout(function(){player.x += 20;}, 700)};
     if (x == 'backward'){setTimeout(function(){player.x -= 20;}, 700)};
     if (x == 'down'){setTimeout(function(){player.y += 20;}, 700)};
     setTimeout(function(){player.glitchCooldown = 120}, 700);
 }
}
function colCheck(shapeA, shapeB) {
    // get the vectors to check against
    var vX = (shapeA.x + (shapeA.width / 2)) - (shapeB.x + (shapeB.width / 2)),
        vY = (shapeA.y + (shapeA.height / 2)) - (shapeB.y + (shapeB.height / 2)),
        // add the half widths and half heights of the objects
        hWidths = (shapeA.width / 2) + (shapeB.width / 2),
        hHeights = (shapeA.height / 2) + (shapeB.height / 2),
        colDir = 'l';
 
    // if the x and y vector are less than the half width or half height, they we must be inside the object, causing a collision
    if (Math.abs(vX) < hWidths && Math.abs(vY) < hHeights) {         // figures out on which side we are colliding (top, bottom, left, or right)         var oX = hWidths - Math.abs(vX),             oY = hHeights - Math.abs(vY);         if (oX >= oY) {
            if (vY > 0) {
                colDir = "t";
                shapeA.y += oY;
            } else {
                colDir = "b";
                shapeA.y -= oY;
            }
        } else {
            if (vX > 0) {
                colDir = "l";
                shapeA.x += oX;
            } else {
                colDir = "r";
                shapeA.x -= oX;
            }
        }
    }
    return colDir;
}
function random() {
 var x = Math.floor((Math.random() * 10) + 1);
    return x;
}

<html>
<head>
 <title>CoRRupTed</title>
 <link rel="stylesheet" href="design.css">
</head>
<body>
<canvas height='250' width='1350' style='border: 1px solid black' id='c'>Your browser do not support the &lt;canvas&gt; tag. Please update your browser.</canvas>
<script src='main.js'></script>
</body>
</html>

如您所见，我的 colCheck 函数无法正常工作。它假定 return colDir 为 'l'、'r'、'b' 或 't'。但是错误显示 "Illegal resturn statement"，所以我认为 colCheck 是 returning colDir 作为 null。因此，在我的代码中，我已经写了var col = colCheck(player, walls[i])，但它仍然不能正常工作。有什么想法吗？

Answer 1

这是因为您没有始终如一地设置代码样式。

该错误表示您的左大括号和右大括号不匹配。

行

 if (Math.abs(vX) < hWidths && Math.abs(vY) < hHeights) {         // figures out on which side we are colliding (top, bottom, left, or right)         var oX = hWidths - Math.abs(vX),             oY = hHeights - Math.abs(vY);         if (oX >= oY) {

应该是。 /* */ 内的评论是我添加的。

   /* DONT make comment run past right edge of screen put them in the line above */
   // figures out on which side we are colliding (top, bottom, left, or right)
   if (Math.abs(vX) < hWidths && Math.abs(vY) < hHeights) {         
       /* DONT use , to separate variable declarations */
       const oX = hWidths - Math.abs(vX); /*Use consts for vars that don't change*/
       const oY = hHeights - Math.abs(vY);         
       if (oX >= oY) {

意外 "Illegal return statement"

Unexpected "Illegal return statement"

html

javascript

canvas

game-physics