为什么for in循环里访问对象的属性是undifined？

Question

var nyc = {

    fullName: "New York City",

    mayor: "Bill de Blasio",

    population: 8000000,

    boroughs: 5

};  

for(var property in nyc) {

    console.log(nyc.property);

    }

//控制台  不应该是属性的值么？

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