js/listener.js

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679 B
JavaScript
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2021-06-23 14:04:33 +00:00
export const listener = (target={}) => {
let callbacks = new Map()
function listen(prop, callback) {
if ("object" == typeof prop && "forEach" in prop)
prop.forEach(prop => this.listen(prop, callback))
else if (callback)
callbacks.set(prop, callback)
else
callbacks.delete(prop)
}
let proxy = new Proxy(target, {
set: (target, prop, value) => {
if (callbacks.has("*")) callbacks.get("*")(value, prop)
if (callbacks.has(prop)) callbacks.get(prop)(value, prop)
return Reflect.set(target, prop, value)
},
get: (target, prop, value) => {
if (prop == "listen")
return listen
else
return Reflect.get(target, prop)
}
})
return proxy
}