for example, get a var a = 123;
through websocket.next time you get the data, a = 321,
how do I listen for changes in an and trigger an event when the value of a changes?
certainly do not want to use polling like setInterval to achieve.
for example, get a var a = 123;
through websocket.next time you get the data, a = 321,
how do I listen for changes in an and trigger an event when the value of a changes?
certainly do not want to use polling like setInterval to achieve.
basic data types, if there is no similar api, object type, you can try setter/getter, your requirements here should be implemented through the Proxy object setter, is very convenient. For example:
function watchChange(object, onChange) {
const handler = {
defineProperty(target, property, descriptor) {
onChange()
return Reflect.defineProperty(target, property, descriptor)
},
deleteProperty(target, property) {
onChange()
return Reflect.deleteProperty(target, property)
},
}
return new Proxy(object, handler)
}
const f = watchChange({}, () => {
console.log('changed')
})
f.a = '1'
delete f.a
for demonstration purposes, I don't write the logic that provides handler.set, which is the proxy method when the value changes.
Mobx Ah
import {observable} from "mobx";
const value = observable.box("123");
console.log(value.get());
// prints '123'
value.observe(function(change) {
console.log(change.oldValue, "->", change.newValue);
});
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