Answers:
编辑:此后已在最新的TS版本中修复。引用@Simon_Weaver对OP帖子的评论:
注意:此问题已得到修复(不确定确切的TS版本)。如您所料,我在VS中收到这些错误:
Index signatures are incompatible. Type '{ firstName: string; }' is not assignable to type 'IPerson'. Property 'lastName' is missing in type '{ firstName: string; }'.
您可以通过在声明和初始化中拆分示例来利用类型化字典,例如:
var persons: { [id: string] : IPerson; } = {};
persons["p1"] = { firstName: "F1", lastName: "L1" };
persons["p2"] = { firstName: "F2" }; // will result in an error
id
符号?似乎没有必要。
id
符号,可以声明字典键的类型。使用上面的声明,您不能执行以下操作:persons[1] = { firstName: 'F1', lastName: 'L1' }
id
符号可以命名为任何您喜欢的名称,其设计旨在使其更易于阅读代码。例如 { [username: string] : IPerson; }
要在打字稿中使用字典对象,可以使用以下界面:
interface Dictionary<T> {
[Key: string]: T;
}
并将其用于您的类属性类型。
export class SearchParameters {
SearchFor: Dictionary<string> = {};
}
使用和初始化此类,
getUsers(): Observable<any> {
var searchParams = new SearchParameters();
searchParams.SearchFor['userId'] = '1';
searchParams.SearchFor['userName'] = 'xyz';
return this.http.post(searchParams, 'users/search')
.map(res => {
return res;
})
.catch(this.handleError.bind(this));
}
我同意thomaux的观点,初始化类型检查错误是TypeScript错误。但是,我仍然想找到一种在正确的类型检查中声明和初始化Dictionary的方法。此实现较长,但是增加了诸如containsKey(key: string)
和remove(key: string)
方法之类的附加功能。我怀疑一旦0.9版本中提供了泛型,就可以简化这一过程。
首先,我们声明基词典类和接口。索引器需要该接口,因为类无法实现它们。
interface IDictionary {
add(key: string, value: any): void;
remove(key: string): void;
containsKey(key: string): bool;
keys(): string[];
values(): any[];
}
class Dictionary {
_keys: string[] = new string[];
_values: any[] = new any[];
constructor(init: { key: string; value: any; }[]) {
for (var x = 0; x < init.length; x++) {
this[init[x].key] = init[x].value;
this._keys.push(init[x].key);
this._values.push(init[x].value);
}
}
add(key: string, value: any) {
this[key] = value;
this._keys.push(key);
this._values.push(value);
}
remove(key: string) {
var index = this._keys.indexOf(key, 0);
this._keys.splice(index, 1);
this._values.splice(index, 1);
delete this[key];
}
keys(): string[] {
return this._keys;
}
values(): any[] {
return this._values;
}
containsKey(key: string) {
if (typeof this[key] === "undefined") {
return false;
}
return true;
}
toLookup(): IDictionary {
return this;
}
}
现在,我们声明Person的特定类型和Dictionary / Dictionary接口。在PersonDictionary中,请注意我们如何重写values()
并toLookup()
返回正确的类型。
interface IPerson {
firstName: string;
lastName: string;
}
interface IPersonDictionary extends IDictionary {
[index: string]: IPerson;
values(): IPerson[];
}
class PersonDictionary extends Dictionary {
constructor(init: { key: string; value: IPerson; }[]) {
super(init);
}
values(): IPerson[]{
return this._values;
}
toLookup(): IPersonDictionary {
return this;
}
}
这是一个简单的初始化和用法示例:
var persons = new PersonDictionary([
{ key: "p1", value: { firstName: "F1", lastName: "L2" } },
{ key: "p2", value: { firstName: "F2", lastName: "L2" } },
{ key: "p3", value: { firstName: "F3", lastName: "L3" } }
]).toLookup();
alert(persons["p1"].firstName + " " + persons["p1"].lastName);
// alert: F1 L2
persons.remove("p2");
if (!persons.containsKey("p2")) {
alert("Key no longer exists");
// alert: Key no longer exists
}
alert(persons.keys().join(", "));
// alert: p1, p3
containsKey(key: string): bool;
不适用于TypeScript 1.5.0-beta。应该更改为containsKey(key: string): boolean;
。
这是受@dmck启发的更通用的Dictionary实现
interface IDictionary<T> {
add(key: string, value: T): void;
remove(key: string): void;
containsKey(key: string): boolean;
keys(): string[];
values(): T[];
}
class Dictionary<T> implements IDictionary<T> {
_keys: string[] = [];
_values: T[] = [];
constructor(init?: { key: string; value: T; }[]) {
if (init) {
for (var x = 0; x < init.length; x++) {
this[init[x].key] = init[x].value;
this._keys.push(init[x].key);
this._values.push(init[x].value);
}
}
}
add(key: string, value: T) {
this[key] = value;
this._keys.push(key);
this._values.push(value);
}
remove(key: string) {
var index = this._keys.indexOf(key, 0);
this._keys.splice(index, 1);
this._values.splice(index, 1);
delete this[key];
}
keys(): string[] {
return this._keys;
}
values(): T[] {
return this._values;
}
containsKey(key: string) {
if (typeof this[key] === "undefined") {
return false;
}
return true;
}
toLookup(): IDictionary<T> {
return this;
}
}
如果要忽略属性,请通过添加问号将其标记为可选:
interface IPerson {
firstName: string;
lastName?: string;
}
现在,有一个库可以在打字稿中提供强类型的,可查询的集合。
这些集合是:
该库称为ts-generic-collections-linq。
GitHub上的源代码:
https://github.com/VeritasSoftware/ts-generic-collections
NPM:
https://www.npmjs.com/package/ts-generic-collections-linq
使用此库,您可以创建集合(如List<T>
)并查询它们,如下所示。
let owners = new List<Owner>();
let owner = new Owner();
owner.id = 1;
owner.name = "John Doe";
owners.add(owner);
owner = new Owner();
owner.id = 2;
owner.name = "Jane Doe";
owners.add(owner);
let pets = new List<Pet>();
let pet = new Pet();
pet.ownerId = 2;
pet.name = "Sam";
pet.sex = Sex.M;
pets.add(pet);
pet = new Pet();
pet.ownerId = 1;
pet.name = "Jenny";
pet.sex = Sex.F;
pets.add(pet);
//query to get owners by the sex/gender of their pets
let ownersByPetSex = owners.join(pets, owner => owner.id, pet => pet.ownerId, (x, y) => new OwnerPet(x,y))
.groupBy(x => [x.pet.sex])
.select(x => new OwnersByPetSex(x.groups[0], x.list.select(x => x.owner)));
expect(ownersByPetSex.toArray().length === 2).toBeTruthy();
expect(ownersByPetSex.toArray()[0].sex == Sex.F).toBeTruthy();
expect(ownersByPetSex.toArray()[0].owners.length === 1).toBeTruthy();
expect(ownersByPetSex.toArray()[0].owners.toArray()[0].name == "John Doe").toBeTruthy();
expect(ownersByPetSex.toArray()[1].sex == Sex.M).toBeTruthy();
expect(ownersByPetSex.toArray()[1].owners.length == 1).toBeTruthy();
expect(ownersByPetSex.toArray()[1].owners.toArray()[0].name == "Jane Doe").toBeTruthy();
Index signatures are incompatible.
Type '{ firstName: string; }' is not assignable to type 'IPerson'.
Property 'lastName' is missing in type '{ firstName: string; }'.