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How to implement monitoring events? A comprehensive analysis from principle to practice
How to implement monitoring events? A comprehensive analysis from principle to practice
Apr 19, 2025 pm 02:12 PM
Easy to understand: Implementation mechanism and practice of monitoring events
In software development, monitoring events is crucial, especially in scenarios where data changes are monitored. This article will explore the underlying mechanism of monitoring events in depth and provide efficient implementation methods to get rid of the constraints of traditional inefficient solutions.
Traditional polling methods, such as repeatedly checking data changes using while loops or timers, although common in embedded systems, have obvious flaws: huge resource consumption and easy to cause system instability.
An even better solution is to use the metaprogramming characteristics of the programming language to achieve the underlying interception of data access.
JavaScript implementation example:
JavaScript provides tools such as Proxy and Object.defineProperty , which can effectively implement listening.
Method 1: Use Proxy
Proxy can intercept the object's property access, thereby implementing listening:
const obj = new Proxy({ bar: 1 }, {
set(target, prop, value) {
console.log('Property update:', prop, ':', value);
target[prop] = value; // The value must be manually set return true; // Return true to indicate successful setting}
});
obj.bar = 2; // Property update: bar: 2
Method 2: Data encapsulation based on publish-subscribe mode
This method gives the data structure event notification capabilities by encapsulating the data structure and introducing a publish-subscribe mode:
// Published by class Emitter {
events = {};
on(event, listener) {
(this.events[event] || (this.events[event] = [])).push(listener);
}
emit(event, ...args) {
(this.events[event] || []).forEach(listener => listener(...args));
}
}
// Data class Data {
store = {};
emitter = new Emitter();
constructor(initialData = {}) {
Object.assign(this.store, initialData);
}
get(key) {
this.emitter.emit('get', key);
return this.store[key];
}
set(key, value) {
this.store[key] = value;
this.emitter.emit('change', key, value);
}
}
// Use example const data = new Data({ count: 0 });
data.emitter.on('change', (key, value) => console.log('Data change:', key, value));
data.set('count', 1); // Data changes: count 1
Through the above methods, we can efficiently monitor data changes, avoid performance and stability problems caused by polling, and thus build more robust applications.
The above is the detailed content of How to implement monitoring events? A comprehensive analysis from principle to practice. For more information, please follow other related articles on the PHP Chinese website!
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