// Record type ensures, we have no double or missing keys, values can be neglected function createKeys(keyRecord: Record<keyof IMyTable, any>): (keyof IMyTable)[] { return Object.keys(keyRecord) as any } const keys = createKeys({ isDeleted: 1, createdAt: 1, title: 1, id: 1 })...
function print(obj: Person, key: Keys) { console.log(obj[key]) } 对于对象类型 key 是 数字或者字符串的情况,keyof 会返回下面的情况: type Arrayish = { [n: number]: unknown }; type A = keyof Arrayish; // type A = number type Mapish = { [k: string]: boolean }; type M = key...
functionprint(obj: Person, key: Keys) {console.log(obj[key]) } 对于对象类型 key 是 数字或者字符串的情况,keyof 会返回下面的情况: typeArrayish= { [n:number]:unknown};typeA= keyofArrayish; //typeA= numbertypeMapish= { [k:string]:boolean};typeM= keyofMapish; //typeM= string | num...
functionprintUser(user:User){Object.keys(user).forEach((key)=>{// 不起作用!console.log(user[key]);// 出错信息如下:// Expression implicitly has an 'any' type because expression of type 'string' can't be used to index type 'User'.// No index signature with a parameter of type 'str...
TypeScript允许我们遍历某种类型的属性,并通过keyof操作符提取其属性的名称,类似Object.keys方法。keyof操作符是在TypeScript 2.1版本引入的,可以用于获取某种类型的所有键,其返回类型是联合类型 interfacePerson{name:string;age:number;location:string;}typeK1=keyofPerson;// "name" | "age" | "location"typeK2=ke...
interfaceIUser{name:string;age:number;number:number;}typeUserKeys=keyofIUser;// "name" | "age" | "number" 联合类型 keyof用于返回对应类型所有Key的联合类型。 工作中关于keyof常用的一个场景。一个函数,接受两个参数,参数一是一个对象,参数二是这个对象中key,如何用TypeScript编写函数 ...
88 return -1 as K; 89 } 90 91 /** 92 * 获取字典所有的键 93 * @returns 键数组 94 */ 95 public Keys(): Array<K> { 96 let values = new Array<K>()//存到数组中返回 97 for (let k in this.items) { 98 if (this.Contains(k as K)) { ...
Map.groupByis similar, but produces aMapinstead of a plain object. This might be more desirable if you need the guarantees ofMaps, you’re dealing with APIs that expectMaps, or you need to use any kind of key for grouping – not just keys that can be used as property names in JavaScri...
You will have to sign up and create API keys on their websites.Private APIs allow the following:manage personal account info query account balances trade by making market and limit orders deposit and withdraw fiat and crypto funds query personal orders get ledger history transfer funds between ...
a =true;// Bar { a, b, c }interfaceBar{a:stringb:number}interfaceBar{c:string}typeKeys="firstname"|"surname";typeDudeType= { [keyinKeys]:string}/** 二、函数参数是对象时,会对对象字面量做额外的属性检查,但却不会对对象引用做检查处理 */interfaceO {a:string;b:number; ...