feat: 单例模式

docs/javaScript/单例模式.md

@@ -0,0 +1,50 @@
+# 单例模式
+
+```js
+// 单例模式
+function SingLeton(name) {
+  this.name = name;
+}
+SingLeton.prototype.getName = function() {
+  console.log(this.name);
+}
+SingLeton.prototype.getInstance = (function() {
+  var instance;
+  return function(name) {
+    if (!instance) {
+      instance = new SingLeton(name);
+    }
+    return instance;
+  }
+})();
+
+var a = SingLeton.getInstance(1);
+var b =SingLeton.getInstance(2);
+console.log(a === b);
+
+
+// 或者
+function S(html) {
+  this.html = html;
+  this.init();
+}
+S.prototype.init = function() {
+  var div = document.createElement('div');
+  div.innerHTML = this.html;
+  document.body.appendChild(div);
+}
+
+var Singleton = (function() {
+  var instance;
+  return function(html) {
+    if (!instance) {
+      instance = new S(html);
+    }
+    return instance;
+  }
+})()
+
+var a = new Singleton('test1');
+var b = new Singleton('test2');
+console.log(a === b)
+```