我通过Google Chrome版本57.0.2987.133运行以下脚本:
var loggingProxyHandler = {
"get" : function(targetObj, propName, receiverProxy) {
let ret = Reflect.get(targetObj, propName, receiverProxy);
console.log("get("+propName.toString()+"="+ret+")");
return ret;
},
"set" : function(targetObj, propName, propValue, receiverProxy) {
console.log("set("+propName.toString()+"="+propValue+")");
return Reflect.set(targetObj, propName, propValue, receiverProxy);
}
};
function onRunTest()
{
let m1 = new Map();
let p1 = new Proxy(m1, loggingProxyHandler);
p1.set("a", "aval"); // Exception thrown from here
}
onRunTest();Run Code Online (Sandbox Code Playgroud)
NOTE: Requires a browser supporting ES2015's ProxyRun Code Online (Sandbox Code Playgroud)
运行时,我看到调用处理程序的get陷阱来返回Map的set函数,然后我收到以下错误:
"Uncaught TypeError: Method Map.prototype.set called on incompatible receiver [object Object]"
at Proxy.set …Run Code Online (Sandbox Code Playgroud)