shijian

事件

事件管理器用于提供事件监听和触发的一系列完善的增强型功能。事件观察者模型只用于监听，并也提供一套相关的增强型功能。

引用和创建实例

import { EventController } from 'datasense';

只需使用关键词new即可创建其实例。

// Create an instance of event controller so that you can on and fire events.
var events = new EventController();

注册事件

// Add event listener.
events.on("click", ev => {
    console.info("Clicked!", ev);
});

In fact, you can have further power to control and get details about this event listener. You can get the listener controller by the 2nd argument in the handler to access these.

// Add event listener.
events.on("click", (ev, listenerController) => {
    // You can get the date of current and latest date raised of this handler.
    // So that you can use these information to add a debounce, throttle or multiple hits event handler.
    console.info(`Clicked at ${listenerController.fireDate.toLocaleTimeString()}!`, ev);

    // You can access the controller for current event listener for status and actions.
    // For example, we can off this listener after 3 times raised.
    if (listenerController.count > 3)
        listener.dispose();
});

To set times that it could raise in the above sample, you can also use following way to implement.

events.on("click", (ev, listenerController) => {
    console.info("Clicked!", ev);
}, null, {
    invalid: 3
});

The property invalid in the 3rd argument is used to dispose the event listener automatically after it is processed equals or more than the given times. You can also set it as true if you want to make it only once raising. And you can set invalidForNextTime property if you still want to process this handler even if it touches the invalid count and then dispose. And you can also set further properties to support debounce, throttle or multiple hits, see task.

The result of on has a number of properties and methods to get the key, fire manually, dispose, etc.

触发事件

You can fire it anywhere.

events.fire("click", "Test only");

And you can also transfer an additional message to the listener.

events.fire("click", "Test only", "Hello!");

// You can get the message by this way,
events.on("click", (ev, listenerController) => {
    console.info(listenerController.message);
});

And you can also send further information such as the sender source in string format or even an additional data. And the listener handler can get this by the properties of listener controller, too.

events.fire("click", "Test only", {
    source: "Somewhere",
    message: "Hello!",
    data: {
        name: "abc",
        value: "defg"
    }
});

订阅

By a simple way to get the notification of event raising, you can just subscribe it.

events.subscribe("click", ev => {
    console.info("Clicked!", ev);
});

And it will return an object with a method dispose to unsubscribe.

临时存储

Sometimes, we need use a variable or more to save the temp data during an event listener is raised for several times. But it has a center place to do so.

events.on("click", (ev, listenerController) => {
    // And you can get a value you saved in previous time.
    // You need identify it by a key since you can set and get a lot.
    if (listenerController.hasStoreData("latestValue"))
        console.info("Latest event argument.", listenerController.getStoreData("latestValue"));

    // You can save something here so that you can use next time.
    listenerController.setStoreData("latestValue", ev);

    // And you can delete it.
    listenerController.removeStoreData("latestValue");
});

These data will not share with other event listeners.

创建观察者模型

And you can create an observable instance which is used for adding listeners with lots of useful options only so that you can send this object to other places.

let eventObs = events.createObservable();

You can also create a single event observable to focus on an event type.

let clickEvent = events.createSingleObservable("click");
clickEvent.on((ev, listenerController) => {
    console.info(`Clicked ${listenerController.count} times!`, ev);
})

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