记一次HEX和RGB互换算法的思考及应用

consthex2rgb= (hex: string=''):string=> {
//  针对于传入错误的hex,即长度不等于7或者不等于4的if(![4,7].includes(hex.length)) {
thrownewError('格式错误') 
  }
letresult=hex.slice(1)
// 如果是颜色叠值, 统一转换成6位颜色值if(result.length===3) {
result=result.split('').map(a=>`${a}${a}`).join('')
  }
constrgb:number[] = []
// 计算hex值for(leti=0, len=result.length; i<len; i+=2) {
rgb[i/2] =getHexVal(result[i]) *16+getHexVal(result[i+1])
  }
functiongetHexVal(letter:string):number {
letnum:number=-1;
switch(letter.toUpperCase()) {
case"A":
num=10break;
case"B":
num=11break;
case"C":
num=12break;
case"D":
num=13break;
case"E":
num=14break;
case"F":
num=15break;
    }
if(num<0) {
num=Number(letter)
    }
returnnum  }
return`rgb(${rgb[0]}, ${rgb[1]}, ${rgb[2]})`}

constrgb2hex= (rgb: string):string=> {
letstr=rgb.replace(/rgb\((.*)\)/g, '$1')
letstrArr=str.split(',').map(t=>t.trim())
letresult:string[] = []
for(leti:number=0, len:number=strArr.length; i<len; i++) {
letcurVal=Number(strArr[i])
letleft=getHexStr(String(Math.floor(curVal/16)))
letright=getHexStr(String(Math.floor(curVal%16)))
result[i] =left+right  }
functiongetHexStr(v:string):string {
letstr:string='';
switch(v) {
case'10':
str="A"break;
case'11':
str="B"break;
case'12':
str="C"break;
case'13':
str="D"break;
case'14':
str="E"break;
case'15':
str="F"break;
    }
if(!str) {
str=v    }
returnstr  }
return`#${result.join('')}`}