ES6个人笔记记录——Proxy4

construct

construct用于拦截new命令

两个参数，target：目标对象，args：构造函数的参数对象

let handler = {
	construct(target,args,newTargets){
		return new target(...arguments);
	}
}

// eg1
let p = new Proxy(function(){},{
	construct : function(target,args){
		console.log('called: ' + args.join(', '));
		return { value : args[0] * 10 };
	}
});

console.log((new p(1)).value);

construct方法返回的必须是一个对象，否则会报错

let p2 = new Proxy(function(){},{
	construct : function(target,argumentsList){
		return 1;
	}
});
// 'construct' on proxy: trap returned non-object ('1')
// new p2();	报错