测试代码:
<html>
<script>
"use strict";
function test(){
Object.defineProperty(window, "_name", {
get : function(){ console.log("gett is called ") },
set : function(newValue){
debugger;
console.log("_name is filled!!!!");
},
enumerable : true,
configurable : true
});
for( var i = 0; i < 2; i++)
console.log(i);
window._name = "2";
};
test();
</script>
通过第5行开始的Object.defineProperty, 给window全局对象的_name属性设置了一个set hook,这样每当该属性被update时,注册的set hook会自动被调用:
测试:
一旦第18行window._name = 2被执行:
set hook会自动触发:
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