zoneless 中文文档教程
这是实验性的
目的
该项目旨在使用 JavaScript 代理和 Angular 的新注入
函数获取组件的 ChangeDetectorRef
并在属性更改时发出通知。
因此,您可以从项目中删除 zone.js
并提高应用程序的性能和包大小。
使用
安装
只需使用npm
安装即可:
npm install zoneless
导入并使用
import { useState } from 'zoneless';
@Component({
selector: 'app-root',
template: `
<h1>Zoneless</h1>
<p>Counter: {{ state.counter }}</p>
<button (click)="increment()">Increment</button>
`,
})
})
export class AppComponent {
state = useState({
counter: 0,
});
increment() {
this.state.counter++; // everything works as usual
}
}
您需要进行更改才能删除zone.js
首先,您需要删除zone.js
来自你的polyfills。从 Angular 15 开始,polyfills 使用 angular.json
中的属性加载:
"projects": {
"my-project": {
"architect": {
"build": {
"options": {
"polyfills": [
"zone.js" // remove this line
]
}
}
}
}
}
并在 main.ts
中禁用使用 ngZone
:
platformBrowserDynamic().bootstrapModule(AppModule, { ngZone: 'noop' })
就是这样,现在您有一个无区域应用程序!
计算属性
您还可以使用从现有状态派生的计算属性:
import { useState, computed } from 'zoneless';
@Component({
selector: 'app-root',
template: `
<h1>Zoneless</h1>
<p>Counter: {{ state.counter }}</p>
<p>Counter * 2: {{ doubleCounter() }}</p>
<button (click)="increment()">Increment</button>
`,
})
})
export class AppComponent {
state = useState({
counter: 0,
});
doubleCounter = computed(
() => this.state.counter * 2,
() => [this.state.counter],
);
increment() {
this.state.counter++; // everything works as usual
}
}
请注意两件事:
compulated
函数将一个函数作为第一个参数,该函数将被调用以获取以下值:计算的属性。- 然后它需要另一个函数,该函数返回依赖项数组。这些是要监视更改的属性。如果其中任何一个发生变化,计算属性将被重新计算。
- 它本身返回一个函数,所以我们需要在模板中调用它来获取值。这是为了让 Angular 的变化检测真正知道值已经改变。如果依赖项没有改变,计算函数将不会。
- 依赖数组实际上让我们依赖于其他几个状态。
使用 Observable -s
async 管道可能不再起作用,但是,您可以使用库提供的另一个函数,< code>useObservable:
import { useObservable } from 'zoneless';
@Component({
selector: 'app-root',
template: `
<h1>Zoneless</h1>
<p>Timer: {{ interval() }}</p>
`,
})
})
export class AppComponent {
state = useObservable(interval(1_000));
}
所以我们不再需要async
管道,但我们仍然可以使用Observable
-s。
请注意,
useObservable
函数返回一个函数,因此您需要调用它来获取值。这是为了让 Angular 的变化检测真正知道值已经改变。
当组件被销毁时,useObservable
函数还会自动取消订阅 Observable
。
已知问题:
目前尚未报告任何问题,但这是实验性的,因此使用风险自负。
贡献
欢迎任何贡献,无论是评论、开放问题、公关还是其他任何内容。如前所述,这是实验性的,因此欢迎任何反馈。目的是进一步实验并看看它是否可以在生产中使用。
THIS IS EXPERIMENTAL
Purpose
This project aims to remove zone.js
by using JavaScript Proxies and the Angular's new inject
function to get the ChangeDetectorRef
of the component and notify when properties are changed.
Thus, you can remove zone.js
from your project and both improve the performance of your application and the bundle size.
Usage
Installation
Just install with npm
:
npm install zoneless
Import and use
import { useState } from 'zoneless';
@Component({
selector: 'app-root',
template: `
<h1>Zoneless</h1>
<p>Counter: {{ state.counter }}</p>
<button (click)="increment()">Increment</button>
`,
})
})
export class AppComponent {
state = useState({
counter: 0,
});
increment() {
this.state.counter++; // everything works as usual
}
}
Changes you need top make to remove zone.js
First, you need to remove zone.js
from your polyfills. Starting from Angular 15, polyfills are loaded using a property in angular.json
:
"projects": {
"my-project": {
"architect": {
"build": {
"options": {
"polyfills": [
"zone.js" // remove this line
]
}
}
}
}
}
And disable using ngZone
in main.ts
:
platformBrowserDynamic().bootstrapModule(AppModule, { ngZone: 'noop' })
That's it, now you have a zoneless application!
Computed properties
You can also use computed properties, derived from an existing state:
import { useState, computed } from 'zoneless';
@Component({
selector: 'app-root',
template: `
<h1>Zoneless</h1>
<p>Counter: {{ state.counter }}</p>
<p>Counter * 2: {{ doubleCounter() }}</p>
<button (click)="increment()">Increment</button>
`,
})
})
export class AppComponent {
state = useState({
counter: 0,
});
doubleCounter = computed(
() => this.state.counter * 2,
() => [this.state.counter],
);
increment() {
this.state.counter++; // everything works as usual
}
}
Notice two things:
- The
computed
function takes a function as the first argument, which is the function that will be called to get the value of the computed property. - Then it takes another function, which returns an array of dependencies. These are the properties that will be watched for changes. If any of them changes, the computed property will be recalculated.
- It itself returns a function, so we need to call it in the template to get the value. This is to make Angular's change detection actually know the value has changed. The computing function will not if no dependencies have changed.
- The dependency array actually let's us depenend on several other states
Using Observable
-s
async
pipe might no longer work, but instead, you can use another function provided by the library, useObservable
:
import { useObservable } from 'zoneless';
@Component({
selector: 'app-root',
template: `
<h1>Zoneless</h1>
<p>Timer: {{ interval() }}</p>
`,
})
})
export class AppComponent {
state = useObservable(interval(1_000));
}
So we no longer need the async
pipe, but we can still use Observable
-s.
Note that the
useObservable
function returns a function, so you need to call it to get the value. This is to make Angular's change detection actually know the value has changed.
The useObservable
function also automatically unsubscribes from the Observable
when the component is destroyed.
Known issues:
No issues have been reported as of now, but this is experimental, so use at your own risk.
Contributing
Any contribution is welcome, be it a comment, and open issue, PR or anything else. As mentioned before, this is experimental, so any feedback is welcome. The aim is to experiment this further and see if it can be used in production.