ngrx signal store 的创建者，marko stanimirovic 在这里描述了 ngrx signalstore：深入了解 angular 中基于信号的状态管理
让我们通过代码示例来探索商店的 api。我们将使用一个包含产品列表和过滤功能的项目。
import { signalstore } from "@ngrx/signals";
export const productstore = signalstore( … );
与迄今为止的任何 ngrx store 一样，可以使用函数 withstate 来提供初始状态，该函数接受对象文字、记录或工厂函数（用于创建动态初始状态）作为输入。
import { signalstore, withstate } from "@ngrx/signals";
const initialproductstate: productstate = { products: [] };
export const productstore = signalstore(
withstate(initialproductstate);
);
import { signalstore, withcomputed, withstate } from "@ngrx/signals";
export const productstore = signalstore(
withstate(initialproductstate),
withcomputed(({products}) => ({
averageprice: computed(() => {
const total = products().reduce((acc, p) => acc + p.price, 0);
return total / products().length;
})
})),
import { signalstore, withcomputed, withstate, withmethods } from "@ngrx/signals";
export const productstore = signalstore(
withstate(initialproductstate),
withcomputed(({products}) => ({
averageprice: computed(() => {
const total = products().reduce((acc, p) => acc + p.price, 0);
return total / products().length;
})
})),
// crud operations
withmethods((store,
productservice = inject(productservice),
) => ({
loadproducts: () => {
const products = tosignal(productservice.loadproducts())
patchstate(store, { products: products() })
},
addproduct: (product: product) => {
patchstate(store, { products: [...store.products(), product] });
},
// ...
})),
withmethods & withcompulated 获取工厂函数并返回可以使用存储访问的方法和计算信号的字典。它们还在注入上下文中运行，这使得可以将依赖项注入到它们中。
import { withhooks } from "@ngrx/signals";
export const productstore = signalstore(
withhooks((store) => ({
oninit() {
// load products when the store is initialized
store.loadproducts();
},
})),
);
使用实体
export const productstorewithentities = signalstore(
withentities<product>(),
// crud operations
withmethods((store,
productservice = inject(productservice),
) => ({
loadproducts: () => {
const products = tosignal(productservice.loadproducts())();
patchstate(store, setallentities(products || []));
},
updateproduct: (product: product) => {
productservice.updateproduct(product);
patchstate(store, setentity(product));
},
})),
</product>
可以添加以“with”开头的多个功能，但它们只能访问之前定义的功能。
使用
signalstorefeature - 用于扩展商店的功能。
对于大型企业应用程序来说，商店可能会变得复杂且难以管理。在为项目编写功能和组件时，拆分得越好、越细，就越容易管理、维护代码和为其编写测试。
但是，考虑到 signalstore 提供的 api，除非相应地拆分代码，否则存储可能会变得难以管理。 signalstorefeature 适合将功能（或组件）的特定功能提取到独立的可测试函数中，该函数可能（并且理想情况下）可以在其他商店中重用。
export const productstore = signalstore(
// previous defined state and methods
// externalizing filtering options
withfilteringoptions(),
);
export function withfilteringoptions() {
return signalstorefeature(
// filtering operations
withmethods(() => ({
getproductsbetweenpricerange: (lowprice: number, highprice: number, products: array<product>, ) => {
return products.filter(p => p.price >= lowprice && p.price ) => {
return products.filter(p => p.category === category);
},
})),
);
}
</product>
现在是
signalstorefeature 的示例，它展示了跨多个商店重用 signalstorefeature 的可能性。
从“@ngrx/signals”导入{ patchstate, signalstorefeature, withmethods }；
export function withCrudOperations() {
return signalStoreFeature(
withMethods((store) => ({
load: (crudService: CrudOperations) => crudService.load(),
update: (crudableObject: CRUD, crudService: CrudOperations) => {
crudService.update(crudableObject);
patchState(store, setEntity(crudableObject));
},
}),
));
}
export interface CrudOperations {
load(): void;
update(crudableObject: CRUD): void;
}
// Product & Customer services must extend the same interface.
export class ProductService implements CrudOperations {
load(): void {
console.log('load products');
}
update(): void {
console.log('update products');
}
}
export class CustomerService implements CrudOperations {
load(): void {
console.log('load customers');
}
update(): void {
console.log('update customers');
}
}
// and now let’s add this feature in our stores
export const ProductStore = signalStore(
withCrudOperations(),
);
export const CustomerStore = signalStore(
withCrudOperations(),
);
ngrx 工具包实用程序包
由于易于扩展，已经有一个名为 ngrx-toolkit 的实用程序包，旨在向信号存储添加有用的工具。
注入signalstore
{providedin: ‘root’} 或在组件、服务、指令等的提供者数组中
深度信号
补丁状态
接收方法
结论性想法
对于大型应用程序来说，它的可靠性还有待证明，尤其是作为全球商店应用时。
目前我认为这是对默认 signal api 的一个很好的补充，使其成为管理的一个不错的选择：
其他资源：
https://www.stefanos-lignos.dev/posts/ngrx-signals-store
https://www.angulararchitects.io/blog/the-new-ngrx-signal-store-for-angular-2-1-flavors/（关于该主题的 4 篇文章）
https://ngrx.io/guide/signals