这可能是一些非常简单和愚蠢的东西，但为什么它没有返回任何东西？ 我有这个简单的类方法：
checkCollision(event) {
let eventX = event.clientX - canvasRect.left;
let eventY = event.clientY - canvasRect.top;
if (this.centerX - eventX <= this.radiusX && this.centerX - eventX >= (this.radiusX/-1) && this.centerY - eventY <= this.radiusY && this.centerY - eventY >= (this.radiusY/-1)) {
console.log(true);
return true;
} else {
console.log(false);
return false;
}
}
但在浏览器中运行时，它的输出是
> obj.checkCollision({clientX: 200, clientY: 200})
false
<- undefined
为什么它没有返回任何东西？console.log正在运行，但没有返回值
![[웹 프런트엔드] Node.js 빠른 시작](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
我为你使用的变量添加了一些任意值，但是我能够使你的代码像这样工作：
const canvasRect = { left: 50, top: 50 }; const obj = { centerX: 100, centerY: 100, radiusX: 100, radiusY: 100, checkCollision(event) { let eventX = event.clientX - canvasRect.left; let eventY = event.clientY - canvasRect.top; if ( this.centerX - eventX <= this.radiusX && this.centerX - eventX >= this.radiusX / -1 && this.centerY - eventY <= this.radiusY && this.centerY - eventY >= this.radiusY / -1 ) { return true; } else { return false; } }, }; console.log(obj.checkCollision({ clientX: 200, clientY: 200 })); // >>> True另外，一个小提示。当你根据布尔表达式明确返回
true或false时，你也可以直接返回布尔表达式本身。const canvasRect = { left: 50, top: 50 }; const obj = { centerX: 100, centerY: 100, radiusX: 100, radiusY: 100, checkCollision(event) { let eventX = event.clientX - canvasRect.left; let eventY = event.clientY - canvasRect.top; return ( this.centerX - eventX <= this.radiusX && this.centerX - eventX >= this.radiusX / -1 && this.centerY - eventY <= this.radiusY && this.centerY - eventY >= this.radiusY / -1 ); }, }; console.log(obj.checkCollision({ clientX: 200, clientY: 200 })); // >>> True