萌新！typescript对象里中括号引用应该怎么写才正确？万分感谢

Question

constTween={Linear:(t:number,b:number,c:number,d:number)=>(c*t)/d+b,Quad:{easeIn:(t:number,b:number,c:number,d:number)=>c*(t/=d)*t+b,easeOut:(t:number,b:number,c:number,d:number)=>-c*(t/=d)*(t-2)+b,easeInOut:(t:number,b:number,c:number,d:number)=>((t/=d/2){const[name,func]=tween.split('.');if(!func)returnTween.Linear;//Tween[name]这里会报错//elementimplicitlyhasananytypebecauseexpressionoftypestringcantbeusedtoindexreturnTween[name][func];};谢过各位大佬

Answer 1

TypeScript目前还不支持字面量类型拆分组合，你可以
Tween扁平化，不搞多层。
强制转换split出来的类型，这需要你同时手动维护两个type。
或者tween用string类型，对split出来的结果做额外判断，确保Tween中有对应的域。
按2的例子：
constTween={
Linear:(t:number,b:number,c:number,d:number)=>(c*t)/d+b,
Quad:{
easeIn:(t:number,b:number,c:number,d:number)=>c*(t/=d)*t+b,
easeOut:(t:number,b:number,c:number,d:number)=>-c*(t/=d)*(t-2)+b,
easeInOut:(t:number,b:number,c:number,d:number)=>((t/=d/2)<1?(c/2)*t*t+b:(-c/2)*(--t*(t-2)-1)+b),
}
}
typeTweenFunc=
|'Linear'
|'Quad.easeIn'
|'Quad.easeOut'
|'Quad.easeInOut';
+typeTweenNameFuncPair=
+|['Linear']
+|['Quad','easeIn']
+|['Quad','easeOut']
+|['Quad','easeInOut']
exportdefault(tween:TweenFunc)=>{
+constpair=tween.split('.')asTweenNameFuncPair;
+if(!pair[1])returnTween.Linear;
+returnTween[pair[0]][pair[1]];
};