Detailed introduction to the namespace event listener nsevent (code example)

This article brings you a detailed introduction (code example) about the namespace event listener nsevent. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you. .

The main reason for this module is to monitor the status interaction between two pages during WeChat development.

For example, pageA and pageB have two pages. PageA has favorites and pageB has the same favorites. item, listen to the same event

// 收藏事件改变
nsevent.on('collectChange', () => {
    // 刷新列表数据
})

Then operating the collect event on pageA will trigger the collectChange callback on its own page. At this time, nsevent comes in handy,

State it like this on pageA

// 收藏事件改变
nsevent.on('collectChange', () => {
    // 刷新列表数据
}, 'pageA')

Triggering the event of pageA on pageB will not trigger the callback of its own page

// 触发collectChange事件
NSEvent.emit('collectChange', params, { ns: ['pageA'] });

You can also trigger the collectChange event of pageA and pageB on pageC

// 触发collectChange事件
NSEvent.emit('collectChange', params, { ns: ['pageA', 'pageB'] });

nsevent document

Event emitter with namespace-event emitter with namespace

Installation and use

npm i nsevent --save

const nsevent = require('nsevent');

// 浏览器
<script src="dist/nsevent.umd.js"></script>

on(eventName, fn, namespace)

Parameter	Required	Description
eventName	is the	listening event name
fn	is the	callback function
namespace	No	Namespace

NSEvent.on('add', (a, b) => {
  console.log(a, b);
});

NSEvent.on('add', (a, b) => {
  console.log(a, b, 'ns');
}, 'ns');

// 1, 2
// 1, 2, 'ns'
NSEvent.emit('add', a, b);

once(eventName, fn)

Parameter	Required	Description
eventName	is the	listening event name
fn	is the	callback function

NSEvent.once('add', (a, b) => {
  console.log(a, b);
});

NSEvent.emit('add', 1, 2);      // 1, 2
NSEvent.emit('add', 1, 2);      // nothing

emit(eventName, arg1, arg2, ..., object)

##eventName is the listening event namearg[1,2,3...]NoThe value passed to the callback functionobjectNo{The last passed object, ns: ['ns'] } You can specify the namespace to trigger the event

NSEvent.on('fire', () => {
  console.log('fire ns');
}, 'ns');

NSEvent.on('fire', () => {
  console.log('fire ns2');
}, 'ns');

NSEvent.on('fire', () => {
  console.log('fire');
});

NSEvent.emit('fire');     // fire ns, fire ns2, fire
console.log("======");
NSEvent.emit('fire', 1, 2, { ns: [] });     // nothing
NSEvent.emit('fire', 1, 2, { ns: ['ns'] }); // fire ns, fire ns2

Parameter	Required	Description

off(eventName, [string|function|array])

##Parameters#eventName isListening event namefunction##string#functionSpecify function to unbind Specify the name through the array Space or function unbinding

Required	Description
				##string
array	No	Unbind callback function
Specify the namespace to unbind
				#array
			const NSEvent = require('../dist/nsevent.cjs'); NSEvent.on('fire', () => {   console.log('fire ns'); }, 'ns'); NSEvent.on('fire', () => {   console.log('fire ns'); }, 'ns'); NSEvent.on('fire', () => {   console.log('fire1'); }, 'ns1'); NSEvent.emit('fire');   // fire ns, fire ns, fire1 console.log('=========='); NSEvent.off('fire', ['ns']); NSEvent.emit('fire');   // fire1 console.log('=========='); NSEvent.off('fire', 'ns1'); NSEvent.emit('fire');   // none

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