并且您想要一个简单的具有编译时和运行时安全性的string-to-Enum转换器，下面的方法效果很好：...
EN我一直在寻找可以从string获取enum的答案，但在我的例子中，枚举值具有不同的对应字符串值。OP对Color...
以下代码可用于在 TypeScript 中创建 enum: enum e { hello = 1, world = 2 }; 并且可以通过以下方式访问这些值: e.hello; e.world; 如何使用字符串值创建 enum? enum e { hello = "hello", // error: cannot convert string to e world = "world" // error }; 原文由 FacePalm 发布,翻译...
functionfn(x:string) {console.log("Hello, "+ x.toLowerCase()); }typeStringOrNumberFunc=(ns:string|number) =>void;letfunc:StringOrNumberFunc= fn;// 不能将类型“(x: string) => void”分配给类型“StringOrNumberFunc”。// 参数“x”和“ns” 的类型不兼容。// 不能将类型“string | num...
enumDirection{Up="UP",Down="DOWN",Left="LEFT",Right="RIGHT",}letmove:Direction=Direction.Up;// "UP" 实用场景:定义有限的选项(如状态码、方向)。 8.类型守卫 (Type Guards) 通过条件判断收窄类型范围。 functionisString(value:any):valueisstring{returntypeofvalue==="string";}functionprocess(value...
4.2. For String Enums – Convert String to Enum However, the same approach will not work for string enums because TypeScript doesn’t automatically generate the reverse mapping in the case of string enums. As a result, attempting to access a string enum value using a string key like App...
When we print this enum value in console, it prints enum variable numeric value like in the above example it prints 4 as 4 is the assigned value of Green.If we want to print enum name instead of number then we can assign it to any string variable and prints it....
类型断言Type Assertion可以用来手动指定一个值的类型,由于<Type>value的语法容易与TSX冲突,所以通常都是使用value as Type的语法。通常当TypeScript不确定一个联合类型的变量到底是哪个类型的时候,我们只能访问此联合类型的所有类型中共有的属性或方法。 interface Cat { name: string; run(): void; } interface Fis...
In TypeScript, string literals allow you to specify the exact value a string must have in it’s lifespan. You can assume it a form as ‘string based enum’ which also is named group of string constants. TypeScript Enum In TypeScript, enums are set of named constants. Though it is op...
const x = "hello" as number;// Conversion of type 'string' to type 'number' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.有的时候，这条规则会显得非常保守，阻止了你原本有效的类型转换。如果发生...