Accessing nested objects in javascript

Question

I am trying to run some JavaScript, but it is not working.

I have an object with two properties that are also objects.

var people = {
        me: {
            name: "Hello"
        },

        molly: {
            name: "Molly"
        }
    };

And I am trying to make a function that uses a for/in statement and an if statement to list the properties of people.

var search = function (x) {
        for (var a in people) {
            if (people.a.name === x) {
                return people.a;
            }
        }
    };

So the function loops through the properties of people and assigns them to the variable a. Therefore people.a will be equal to a property of people. Then the function returns the property (people.a).

So if I type in me as parameter x, will the function should return the properties for the me object? I put this code in jsLint and jsHint and it passed, but I decided to remove the corrections because they were useless.

I then want to print the object properties in the browser:

var print = search("me");
document.getElementById("p").innerHTML(print);

I have this linked to an html document, with a

tag id "p". I have tested javascript in the html document already, so I know that the javascript document is linked properly.

But the code will not work. Does anyone have any suggestions?

I have it working now thanks to the answers. But I thought that it would only print "Hello" to the screen, not { name: "Hello"}.

With your example, search("me") wouldn't return anything because there aren't any people with name: "me". Maybe you meant search("Hello"). Either way, there is another problem and the answers below describe that... — lbstr
– lbstr, Commented Aug 12, 2013 at 22:07

McGarnagle · Accepted Answer · 2013-08-12 22:05:13Z

3

You need to use people[a], not people.a. The former looks for a property with the name of the value stored in a; the latter looks for a property literally named "a", which of course doesn't exist.

for (var a in people) {
    if (people[a].name === x) {
        return people[a];
    }
}

Fiddle here.

Also, I think you meant search("Hello"), right? If not, then it would just be var search = function(x) { return people[x]; }.

edited Aug 12, 2013 at 22:05

answered Aug 12, 2013 at 21:59

McGarnagle

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2 Comments

user2620463 Over a year ago

Yes I did mean search("Hello"). So if the properties of an object are an object I need to use [ ] instead of . ? Also, if I added more properties to the me object would this code also print them onto the screen?

dc5 Over a year ago

@user2620463 - if I understand your statement about "properties of an object are an object", that isn't correct. If you are trying to access the property of an object using the value of a variable, then you need to use bracket notation. In this case, when the variable a === "me", people[a] is equivalent to people["me"] is equivalent to people.me

Lochemage · Accepted Answer · 2013-08-12 21:59:59Z

1

people.a.name

you need to use the bracket operator if you want to access an item by name. Using people.a is literally searching for a member named 'a' instead of a member with the same name as the value of a.

Try:

people[a].name

instead.

answered Aug 12, 2013 at 21:59

Lochemage

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Comments

Nabil Kadimi · Accepted Answer · 2013-08-12 22:07:25Z

0

4 errors in your code:

replace people.a with people[a]
replace innerHTML() with innerHTML
set HTML like this: document.getElementById("p").innerHTML = print.name;
As in a previous answer, search by name

Code: http://jsfiddle.net/nabil_kadimi/vVSPG/

answered Aug 12, 2013 at 22:07

Nabil Kadimi

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2 Comments

user2620463 Over a year ago

Thank! This is exactly what I wanted to do. Do I only use [ ] if the property is another object?

Nabil Kadimi Over a year ago

You would use obj.a or obj['a'] if if the object has the property a that you are interested in.

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