javascript OOP 中的公共方法
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Public methods in javascript OOP
提问by Howie
I want to make a javascript class with methods which I can call within the class as well as outside of the class. I want to make a "public" method, if you will. I want getTextAreaElementand appendTextAreato be such methods.
我想使用可以在类内和类外调用的方法创建一个 javascript 类。如果您愿意，我想创建一个“公共”方法。我想要getTextAreaElement并且appendTextArea成为这样的方法。
I've shown a snippet of best code I could come up with so far. I've also tried defining the methods as prototypes as well as within the class (this.func = ...). But that only allowed me to call the method outside (new Socket().appendTextArea("osgjr89");) but NOTwithin the class itself! The code snippet below shows the exact opposite implementation where I can't call the method outside of the class but cancall it within.
我已经展示了迄今为止我能想出的最佳代码片段。我还尝试将方法定义为原型以及在类 ( this.func = ...) 中。但这仅允许我在 ( new Socket().appendTextArea("osgjr89");)之外调用该方法，而不能在类本身内调用！下面的代码片段显示了完全相反的实现，我不能在类外调用该方法，但可以在类内调用它。
Error:
错误：
Uncaught TypeError: Object #Socket has no method 'appendTextArea'
未捕获的类型错误：对象 #Socket 没有方法“appendTextArea”
socket.js:
套接字.js：
function Socket() {
var socket;
var canvas = document.getElementById('c');
var context = canvas.getContext("2d");
if (window.WebSocket) {
socket = new WebSocket("ws://localhost:9012/websocket");
socket.binaryType = 'arraybuffer';
socket.onopen = onopen;
socket.onmessage = onmessage;
socket.onerror = onerror;
socket.onclose = onclose;
} else {
alert("Your browser does not support Web Socket.");
}
function getTextAreaElement() {
return document.getElementById('responseText');
}
function appendTextArea(newData) {
var el = getTextAreaElement();
el.value = el.value + '\n' + newData + " :)";
}
function onopen(event) {
getTextAreaElement().value = "Web Socket opened!";
}
/*[...]*/
}
main.js (loads after socket.js)
main.js（在 socket.js 之后加载）
$(document).ready(function() {
var s = new Socket();
s.appendTextArea("osgjr89"); // ERROR!
});
UPDATED socket.js:
更新的 socket.js：
function Socket() {
[...]
if (window.WebSocket) {
socket = new WebSocket("ws://localhost:9012/websocket");
socket.binaryType = 'arraybuffer';
socket.onopen = this.onopen;
socket.onmessage = this.onmessage;
socket.onerror = this.onerror;
socket.onclose = this.onclose;
} else {
alert("Your browser does not support Web Socket.");
}
this.getTextAreaElement = function() {
return document.getElementById('responseText');
}
this.appendTextArea = function(newData) {
var el = this.getTextAreaElement();
el.value = el.value + '\n' + newData + " :)";
}
this.onopen = function(event) {
this.getTextAreaElement().value = "Web Socket opened!";
}
[...]
}
回答by bfavaretto
All public methods must be declared as properties, not variables/functions. So, you have to change stuff like this:
所有公共方法都必须声明为属性，而不是变量/函数。所以，你必须改变这样的东西：
function getTextAreaElement() {
return document.getElementById('responseText');
}
into
进入
this.getTextAreaElement = function() {
return document.getElementById('responseText');
}
回答by Beat Richartz
If you do this.func = function() {}, you can call the function inside the Constructor (Socketin your case) using this.func()as well as outside using:
如果你这样做this.func = function() {}，你可以调用构造函数内部的函数（Socket在你的情况下）使用this.func()以及外部使用：
var s = new Socket();
s.func();
