CODEWITHSUNDEEP
javascriptloopsobject
cinnaroll45
cinnaroll45

Reputation: 2790

How to use for/in loop to transfer object properties?

I have an object that's nested like the example below. 

var posts = {
        "post1": {
            "slug": "slug1",
            "title": "title1",
        },
        "post2": {
            "slug": "slug2",
            "title": "title2",
    }
};

I'm trying to write a for/in loop that will allow me to iterate through this object.

var testLoop = function () {
    for (var prop in posts){
        post = prop;
        console.log(post); // Outputs post1 and post2 
        console.log(post.slug); // Outputs undefined
    }
}

As seen above, I can't store and later access the properties of each iterated object. Only the name of the object is stored and logged. When I run typeof, I see that it's not even an object, it's just a string.

How can I correctly store each iterated properties as objects (post1, post2 etc.) during the loop so I can access their properties using dot notation?

Upvotes: 1

Views: 68

Answers (1)

Brian Glaz
Brian Glaz

Reputation: 15666

When you use

for (var prop in posts){ ... }

It loops over the string keys in the posts object.

The main point here is that prop will be a string, and not an object like your current code is expecting.

As users in the comments suggested, because prop is the object key as a string, you need to use posts[prop] to refer to the actual object.

Here is some updated code.

var testLoop = function () {
    for (var prop in posts){
        post = posts[prop]; // ** this is line that needs to be modified **
        console.log(post); // Outputs post object 
        console.log(post.slug); // this should work now
    }
}

Upvotes: 1

Related Questions