javascript 问题与开关语句找到不大小写： "none"

Question

我的代码必须看看是否有一个球在mapPoint，然后改变像素的颜色，其中球是由球的颜色。下面是我的代码:

function UpdateColorInMapPoints(mapPointIndexs)
{
mapPointIndexs.forEach(mapPointIndex => {
var mapPointData=ballsMap[mapPointIndex]
var ballsAtTheMapPoint=ballsMap[mapPointIndex].balls;
var temperature;
if(ballsAtTheMapPoint.length>0)
{
temperature=balls[ballsAtTheMapPoint[ballsAtTheMapPoint.length-1]].temperature;
}else
{
temperature="none1";
}
var column,line=0;
while(line<scale)
{
column=0;
while(column<scale)
{
putTemperatureColorAt(temperature,(mapPointData.horizontalPosition*scale+column)*4+(mapPointData.verticalPosition*scale+line)*4*imgWidth*scale);
column++;
}
line++;
}
});
canvasContext.putImageData(ImgData,0,0);
}
function putTemperatureColorAt(temperature,index)
{
switch(Math.round(temperature))
{
case -5:
ImgData.data[index+0]=0;
ImgData.data[index+1]=255;
ImgData.data[index+2]=255;
ImgData.data[index+3]=255;
break;
case -4:
ImgData.data[index+0]=50;
ImgData.data[index+1]=255;
ImgData.data[index+2]=200;
ImgData.data[index+3]=255;
break;
case -3:
ImgData.data[index+0]=100;
ImgData.data[index+1]=255;
ImgData.data[index+2]=150;
ImgData.data[index+3]=255;
break;
case -2:
ImgData.data[index+0]=150;
ImgData.data[index+1]=255;
ImgData.data[index+2]=100;
ImgData.data[index+3]=255;
break;
case -1:
ImgData.data[index+0]=200;
ImgData.data[index+1]=255;
ImgData.data[index+2]=50;
ImgData.data[index+3]=255;
break;
case 0:
ImgData.data[index+0]=255;
ImgData.data[index+1]=255;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;
case 1:
ImgData.data[index+0]=255;
ImgData.data[index+1]=200;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;
case 2:
ImgData.data[index+0]=255;
ImgData.data[index+1]=150;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;
case 3:
ImgData.data[index+0]=255;
ImgData.data[index+1]=100;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;
case 4:
ImgData.data[index+0]=255;
ImgData.data[index+1]=50;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;
case 5:
ImgData.data[index+0]=255;
ImgData.data[index+1]=0;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;
case "none1":
ImgData.data[index+0]=0;
ImgData.data[index+1]=0;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;
default:
console.log("Impossible to find color:"+temperature);
}
}

当我运行代码时，控制台显示:"Impossible to find color: none1"这意味着温度= ' none ';但是如果temperature=& none &;开关的输出不应该是默认的，因为有大小写"none1":

case "none1":
ImgData.data[index+0]=0;
ImgData.data[index+1]=0;
ImgData.data[index+2]=0;
ImgData.data[index+3]=255;
break;

我很不明白哪里不对，我希望我的英语不是太差。

Answer 1

将开关更改为:

switch (isFinite(temperature) ? Math.round(temperature) : temperature) {
// ...
}

您希望避免对非有限值进行舍入，即无效的Number。

---

const process = (temperature) => {
switch (isFinite(temperature) ? Math.round(temperature) : temperature) {
case 0: return 'Zero';
case 1: return 'One';
case 'none1': return 'None';
default: throw new Error(`Unknown temperature: ${temperature}`);
}
};
console.log(process(0.2));       // Zero
console.log(process(0.8));       // One
console.log(process('none1'));   // None
console.log(process(undefined)); // throw Error

Answer 2

检查开关语句

console.log(Math.round("none1"))