This is probably something very simple and stupid, but why doesn't it return anything? I have this simple class method:
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;
}
}
But when running in the browser, its output is
> obj.checkCollision({clientX: 200, clientY: 200})
false
<- undefined
Why doesn't it return anything? console.log is running but no return value
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I added some arbitrary values to the variables you used, but I was able to get your code to work like this:
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 })); // >>> TrueAlso, a little tip. When you explicitly return
trueorfalsebased on a Boolean expression, you can also directly return the Boolean expression itself.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