The search function in the following code is not working and I believe it has something to do with the For...In loop but I am new to JS and unsure why:
var friends = {
bill: {
firstName: "bill",
lastName: "smith",
number: 1,
address: ["1"]
},
steve: {
firstName: "steve",
lastName: "smith",
number: 2,
address: ["2"]
}
};
var list = function(list) {
for(var item in list) {
console.log(item);
}
};
var search = function(name) {
for(var friend in friends) {
if(friend.firstName === name) {
console.log(friend);
return friend;
}
}
};
search("steve");
The for in
loop iterates over keys, not values.
friend
is a string holding the name of each property.
To get the value, use friends[friend]
.
Great documentation of the for..in loop can be found on mdn. Where variable
is assigned through each iteration to "a different property name".
You also may not need to loop through each friend. What if you changed your search function to use hasOwnProperty
on the object:
var search = function(name) {
if(friends.hasOwnProperty(name)){
return friends[name];
}
};
This would check that you have a property of name
in the object friends
and return it. Here's a quick EXAMPLE.
来源:https://stackoverflow.com/questions/18452059/javascript-for-in-syntax-issue