这个for循环和if语句怎么理解，控制台输出的理解不了。

Question

var friends = {

    bill: {

        firstName: "Bill",

        lastName: "Gates",

        number: "[phone]",

        address: ['dixia']

    },

    steve: {

        firstName: 'Steve',

        address: ['tianshang']

        }

};

var search = function(name) {

    for(var key in friends) {

        if(friends[key].firstName === name) {

            console.log(friends[key]);

            return friends[key];

        }

    }

};

search("Steve");

//控制台

{ firstName: 'Steve', address: [ 'tianshang' ] }

{ firstName: 'Steve', address: [ 'tianshang' ] }

{ firstName: 'Steve', address: [ 'tianshang' ] }

{ firstName: 'Bill',

  lastName: 'Gates',

  number: '[phone]',

  address: [ 'dixia' ] }

{"firstName":"Steve","address":["tianshang"]}

Answer 1

找出与给定参数一致的内容（console.log输出一个，return输出一个）