gs-events
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JavaScript
import { Event, EventPhase, EventDispatcher } from "..";
import assert from "assert";
describe("事件派发器(EventDispatcher)", () => {
it("基本用法", () => {
const dispatcher = new EventDispatcher();
const handler = ( evt ) => {};
/// 校验返回类型
assert.strictEqual(dispatcher.hasEventListener("any"), false, "hasEventListener() 没有返回 Boolean 类型的值");
/// 注册侦听器
dispatcher.addEventListener("basic", handler);
assert.strictEqual(dispatcher.hasEventListener("basic"), true, "注册侦听器失败");
/// 移除侦听器
dispatcher.removeEventListener("basic", handler);
assert.strictEqual(dispatcher.hasEventListener("basic"), false, "移除侦听器失败");
/// 无效的侦听器
assert.throws(() => {
dispatcher.addEventListener("throws");
}, "注册空的侦听器时没有抛出异常");
/// 捕获阶段
dispatcher.addEventListener("capture", handler, true);
assert.strictEqual(dispatcher.hasEventListener("capture"), true, "注册捕获阶段的侦听器失败");
dispatcher.removeEventListener("capture", handler); // 确保这里不会删除侦听器。
assert.strictEqual(dispatcher.hasEventListener("capture"), true, "意外移除了捕获阶段的侦听器");
dispatcher.removeEventListener("capture", handler, true); // 移除捕获阶段的侦听器。
assert.strictEqual(dispatcher.hasEventListener("capture"), false, "移除捕获阶段的侦听器失败");
/// 指定事件阶段
dispatcher.addEventListener("capture", ( evt ) => {}, { "useCapture": false });
/// 指定作用域
const scope = {};
dispatcher.addEventListener("scope", function( evt ) {
assert.strictEqual(this, scope, "当前作用域与指定的作用域不相同");
}, { scope });
dispatcher.dispatchEvent(new Event("scope"));
/// 一次性侦听器
dispatcher.addEventListener("once", ( evt ) => {}, { "once": true });
dispatcher.dispatchEvent(new Event("once"));
assert.strictEqual(dispatcher.hasEventListener("once"), false, "一次性侦听器在执行后没有被自动移除！");
/// 侦听器优先级
let priority = -1;
dispatcher.addEventListener("priority", ( evt ) => {
assert.strictEqual(priority, 2, "高优先级的侦听器没有提前的被执行！");
priority = 1;
}, { "priority": 1 });
dispatcher.addEventListener("priority", ( evt ) => {
assert.strictEqual(priority, -1, "提前执行了其他低优先级的侦听器。")
priority = 2;
}, { "priority": 2 });
dispatcher.addEventListener("priority", ( evt ) => {
assert.strictEqual(priority, 1, "优先级执行顺序错误！");
priority = 0;
});
dispatcher.dispatchEvent(new Event("priority"));
assert.strictEqual(priority, 0, "最终值不是低优先级的侦听器的值。");
});
it("进阶用法", () => {
const dispatcher = new EventDispatcher();
/// 使用 Symbol 作为事件类型。
let type = Symbol("symbol event");
let value = 0;
dispatcher.addEventListener(type, ( evt ) => {
value = 1;
});
dispatcher.dispatchEvent(type);
assert.strictEqual(value, 1, "使用 Symbol 作为事件类型注册/派发事件失败！");
/// 实现 IEventListener 接口的侦听器。
let listener = {
handleEvent( evt ) {
assert.strictEqual(this, listener, "IEventListener 侦听器的作用域异常！");
}
};
dispatcher.addEventListener("IEventListener", listener);
dispatcher.dispatchEvent("IEventListener");
/// 派发事件时注册新的侦听器。
let state = 1;
let handler = ( evt ) => { state = 2; };
dispatcher.addEventListener("advanced", ( evt ) => {
dispatcher.addEventListener("advanced", handler);
}, { "once": true });
dispatcher.dispatchEvent("advanced");
assert.strictEqual(dispatcher.hasEventListener("advanced"), true, "在派发事件过程中注册事件失败！");
assert.strictEqual(state, 1, "在派发事件过程中注册的事件被意外的执行了。");
dispatcher.dispatchEvent("advanced");
assert.strictEqual(state, 2, "派发事件过程中注册的侦听器在后续派发过程中无法被执行！");
/// 使用非 IEventListenerOptions 类型的对象移除事件。
dispatcher.removeEventListener("advanced", handler, { "useCapture": false });
assert.strictEqual(dispatcher.hasEventListener("advanced"), false, "使用 IEventListenerOptions 类型的值无法移除侦听器。");
/// 派发相同的事件
let event = new Event("same");
assert.throws(() => {
dispatcher.dispatchEvent(event);
dispatcher.dispatchEvent(event);
}, "多次派发同一个事件时没有跑出异常!");
});
it("事件流", () => {
class Node extends EventDispatcher {
constructor( parent = null ) { super(); this.parent = parent; }
}
const root = new Node(null);
const parent = new Node(root);
const child = new Node(parent);
root.addEventListener("through", ( evt ) => {
assert.strictEqual(evt.eventPhase, EventPhase.CAPTURING_PHASE, "事件状态不是捕获阶段。");
}, true);
parent.addEventListener("through", ( evt ) => {
assert.strictEqual(evt.eventPhase, EventPhase.BUBBLING_PHASE, "事件状态不是冒泡阶段。");
});
child.addEventListener("through", ( evt ) => {
assert.strictEqual(evt.eventPhase, EventPhase.AT_TARGET, "事件状态不是目标阶段。");
}, true);
child.addEventListener("through", ( evt ) => {
assert.strictEqual(evt.eventPhase, EventPhase.AT_TARGET, "事件状态不是目标阶段。");
}, false);
child.dispatchEvent(new Event("through", true, true));
/// 默认行为
assert.strictEqual((new Event("default", false, true)).cancelable, true, "事件应该可以取消默认行为！");
child.addEventListener("default", ( evt ) => {
evt.preventDefault();
});
assert.strictEqual(child.dispatchEvent(new Event("default", false, false)), true, "默认行为不能被取消！");
assert.strictEqual(child.dispatchEvent(new Event("default", false, true)), false, "无法取消默认行为！");
/// 事件传递
let isTarget = false;
let isBubble = false;
root.addEventListener("capture", ( evt ) => {
evt.stopPropagation();
}, true);
child.addEventListener("capture", ( evt ) => {
isTarget = true;
});
assert.strictEqual(child.dispatchEvent(new Event("capture", true, true)), false, "派发事件没有传递到目标对象时，应该返回 false。");
assert.strictEqual(isTarget, false, "无法在捕获阶段中断事件传递!");
child.addEventListener("target", ( evt ) => {
evt.stopPropagation();
});
parent.addEventListener("target", ( evt ) => {
isBubble = true;
});
assert.strictEqual(child.dispatchEvent(new Event("target", true, true)), true, "派发事件到达目标对象时，没有取消默认行为则应该返回 true。");
assert.strictEqual(isBubble, false, "无法在目标阶段中断事件传递！");
/// 立刻中断事件传递。
let immediate = 0;
child.addEventListener("immediate", ( evt ) => {
immediate = 1;
evt.stopImmediatePropagation();
});
child.addEventListener("immediate", ( evt ) => {
immediate = 2;
});
child.dispatchEvent(new Event("immediate", true, true));
assert.strictEqual(immediate, 1, "无法立刻中断事件传递！");
});
it("事件代理", () => {
const target = {};
const dispatcher = new EventDispatcher(target);
let success = false;
target.addEventListener("delegate", function( evt ) {
assert.strictEqual(this, target, "事件代理的侦听器的作用域异常！");
success = true;
});
target.dispatchEvent("delegate");
assert.strictEqual(success, true, "创建事件代理失败！");
/**
* 无法被代理的对象。
*/
assert.throws(() => {
new EventDispatcher(new EventDispatcher());
}, "为已经实现事件系统的对象创建代理时没有抛出异常！");
});
});