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

Installation and use

npm i nsevent --save

const nsevent = require('nsevent');

// 浏览器

on(eventName, fn, 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)

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)

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

off(eventName, [string|function|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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