Observer Pattern

Author: skillnull

Example/Observer-Pattern.js

@@ -1 +1,42 @@
-// 观察者模式(Observer Pattern)
+// 观察者模式(Observer Pattern)
+
+class Subject {
+ constructor () {
+ this.state = 0
+ this.observers = []
+ }
+
+ getState () {
+ return this.state
+ }
+
+ setState (state) {
+ this.state = state
+ this.notifyAllObsevers()
+ }
+
+ attach (observer) {
+ this.observers.push(observer)
+ }
+
+ notifyAllObsevers () {
+ for (let ele of this.observers.values()) {
+ ele.update()
+ }
+ }
+}
+
+class Observer {
+ constructor (name, subject) {
+ this.name = name
+ this.subject = subject
+ this.subject.attach(this)
+ }
+ update () {
+ console.log(this.name,this.subject.getState())
+ }
+}
+
+let subject = new Subject()
+let observer = new Observer('observer 1', subject)
+subject.setState('hahaha')