event-emitter

解释： 在小程序开发中，总会遇到事件监听派发的需求，smt-event-emitter是一个订阅发布器。eventsEmitter可通过new EventsEmitter()创建返回。小程序中使用三方npm包方法，见npm使用说明。

方法参数

eventsEmitter对象上的方法

fireMessage方法参数说明

onMessage方法参数说明

onMessage方法的options参数

delHandler方法参数说明：

merge方法参数说明：

代码示例

在开发者工具中预览效果

扫码体验

请使用百度APP扫码

图片示例

安装

  1.     npm install @smt-lib/event-emitter

代码示例1

  1.     // 订阅发布常规用法    const eventsEmitter = new EventsEmitter();     let a = 0;    eventsEmitter.onMessage('addA', message => {        a += message.num;    });    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    console.log(a); // 5

代码示例2

  1.     // 先发布后订阅    const eventsEmitter = new EventsEmitter();    let a = 0;    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    eventsEmitter.onMessage('addA', message => {        a += message.num;    }, {        listenPreviousEvent: true    });    console.log(a); // 10

代码示例3

  1.     // 监听多个type变化    const eventsEmitter = new EventsEmitter();    let a = 0;    eventsEmitter.onMessage(['addA', 'addB'], message => {        a += message.num;    });    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    eventsEmitter.fireMessage({        type: 'addB',        num: 5    });    console.log(a); // 10

代码示例4

  1.     // 监听类型为*时，执行任何fireMessage都会调用回调    const eventsEmitter = new EventsEmitter();    let a = 0;    let b = 0;    eventsEmitter.onMessage('addA', message => {        a += message.num;    });    eventsEmitter.onMessage('*', message => {        b += message.num;    });    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    console.log(b); // 5

代码示例5

  1.     // 删除某个type下的具体回调    const eventsEmitter = new EventsEmitter();    let a = 0;    let b = 0;    const addA = message => {        a += message.num;    };    const addB = message => {        b += message.num;    };    eventsEmitter.onMessage('addA', addA);    eventsEmitter.onMessage('addA', addB);    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    eventsEmitter.delHandler('addA', addA);    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    console.log(a); // 5    console.log(b); // 10

代码示例6

  1.     // 删除所有回调    const eventsEmitter = new EventsEmitter();    let a = 0;    const addA = message => {        a += message.num;    };    eventsEmitter.onMessage('addA', addA);    eventsEmitter.onMessage('addB', addA);    eventsEmitter.fireMessage({        type: 'addA',        num: 5    });    eventsEmitter.delHandler('*');    eventsEmitter.fireMessage({        type: 'addB',        num: 5    });    console.log(a); // 5

代码示例7

  1.     // 融合多条事件流成为一条    const eventsEmitterA = new EventsEmitter();    const eventsEmitterB = new EventsEmitter();    const mergedEventsEmitter = EventsEmitter.merge(eventsEmitterA, eventsEmitterB);    let a = 0;    mergedEventsEmitter.onMessage(['addA', 'addB'], message => {        a += message.num;    });    eventsEmitterA.fireMessage({        type: 'addA',        num: 5    });    eventsEmitterB.fireMessage({        type: 'addB',        num: 5    });    console.log(a); // 10