[k:string]:T}// Array.prototype.map, but for DictfunctionmapDict<T,S>(input:Dict<T>,transform:(item:T,key:string)=>S):Dict<S>{constobj:Dict<S>={};for(letxininput){obj[x]=transform(input[x],x);}returnobj;}// Array.prototype.filter, but for DictfunctionfilterDict<T>(input:...
type Text = string | { text: string }; type NameLookup = Dictionary<string, Person>; type Callback<T> = (data: T) => void; type Pair<T> = [T, T]; type Coordinates = Pair; type Tree<T> = T | { left: Tree<T>, right: Tree<T> }; 1. 2. 3. 4. 5. 6. 7. 8. 9...
interface NumberDictionary { [index: string]: number; length: number; // ok name: string; // Property 'name' of type 'string' is not assignable to 'string' index type 'number'. } 然而,如果一个索引签名是属性类型的联合,那各种类型的属性就可以接受了: interface NumberOrStringDictionary { ...
interface Dictionary<T> { [key: string]: T; } let keys: keyof Dictionary<number>; let keys: string | number let value: Dictionary<number>["foo"]; let value: numberTryIf you have a type with a number index signature, keyof T will just be number....
interface NumberOrStringDictionary { [index: string]: number | string; length: number; // ok, length is a number name: string; // ok, name is a string }Try Finally, you can make index signatures readonly in order to prevent assignment to their indices: interface ReadonlyStringArray { ...
interface Dictionary<T> { [index: string]: T; }; interface NumericDictionary<T> { [index: number]: T; }; const data:Dictionary<number> = { a: 3, b: 4 } 09 使用 const enum 维护常量表 相比使用字面量对象维护常量,const enum 可以提供更安全的类型检查 ...
type Record<K extends keyof any, T> = { [P in K]: T;}; interface Dictionary<T> { [index: string]: T;}; interface NumericDictionary<T> { [index: number]: T;}; const data:Dictionary<number> = { a: 3, b: 4} 09 使用 const enum 维护常量表 相比使用字面量对象维护常量,const...
interface NumberDictionary { [index: string]: number; length: number;//可以,length是number类型name: string//错误,`name`的类型与索引类型返回值的类型不匹配} 最后,可以将索引签名设置为只读,这样就防止了给索引赋值: interface ReadonlyStringArray { ...
C# 存储相同键多个值的Dictionary Console.WriteLine("value:{0}",s); } //9.使用TryGetValue方法获取指定键对应的值...1.HashTable 哈希表(HashTable)表示键/值对的集合。...Hashtable中key-value键值对均为object类型,所以Hashtable可以支持任何类型的keyvalue键值对,任何非 null 对象都可以用作键或值。
interface NumberDictionary { [index: string]: number; length: number; // ok name: string; // Property 'name' of type 'string' is not assignable to 'string' index type 'number'. } 然而,如果一个索引签名是属性类型的联合,那各种类型的属性就可以接受了: ...