在这里,我们将编写一个名为enumToArray的函数,该函数将UserRole枚举作为参数,并返回目标类型: // 将Enum转换为字符串数组的函数functionenumToArray(enumObj:any):UserRoleArray{returnObject.values(enumObj);} 1. 2. 3. 4. 代码解释: enumToArray是我们定义的函数
function someFunction() { // 代码块函数体 const receipts = books.map((b: Book) => { const receipt = payMoney(b.price) return receipt }) // 表达式函数体 const longThings = myValues.filter((v) => v.length > 1000).map((v) => String(v))}如果不需要函数返回值的话，...
布尔(boolean)、数字(number)、字符串(string)、数组(array)、 元祖(tuple)、枚举(enum)、任意(any)、null和undefined 、void、never 指定一个变量的类型var 变量名:类型 = 变量值 如果值的类型不是指定的类型就会报错Type '"xxx"' is not assignable to type 'xxx'. 布尔(boolean): varflag:boolean=true;...
Often in TypeScript, you want to have all of the possible enum keys as an array when working with enums. Typical use cases are dropdown or other selection components based on enums. Using the Object.keys(...) and Object.values(...) methods, it's straightforward to get the enum keys...
Check outGet Distinct Values from an Array in TypeScript When to Use Array.find() in TypeScript Let me tell you where you should use the find() method in TypeScript and where you should not use it. Usefind()when: You want only thefirstmatching element. ...
问在Array<string>中将Record<Enum>转换为TypeScriptEN正如@captain正确地指出的那样，您不能使用map，...
了解了基础的 TS 类型,接口之后,我们开始了解如何给更加复杂的结构注解类型,这就是我们这节里面要引出的函数,进而我们讲解如何对类型进行运算:交叉类型和联合类型,最后我们讲解了最原子类型:字面量类型,以及如何与联合类型搭配实现类型守卫效果。 本文所涉及的源代码都放在了Github[1]或者Gitee[2]上,如果您觉得我们...
按照设计模式中接口单一职责原则, 可以推断payType (readonly ["Alipay", "Wxpay", "PayPal"])是由ReadonlyArray 只读类型和 indexLiteralType 字面量类型组成的联合类型。 typeindexLiteralType = {readonly"0":"Alipay",readonly"1":"Wxpay",readonly"2":"PayPal"};typevalues = indexLiteralType [keyof...
typeIsArray<T> = Textendsany[] ?true:false;functionfoo<Uextendsobject>(x:IsArray<U>) {letfirst:true= x;// Errorletsecond:false= x;// Error, but previously wasn't} Previously, when TypeScript checked the initializer forsecond, it needed to determine whetherIsArray<U>was assignable to ...
In TypeScript, like JavaScript,arrays are homogenous collections of values. We can define an array in the following ways. First, we can declare and initialize the array in the same line: letarray:number[]=[1,2,3];letarray:Array<number>=[1,2,3];letarray:number[]=newArray(1,2,3);...