React TypeError: skills.map is not a function

Question

I have an object skills and I want to iterate over it and map its contents. The object looks like this:

{
    "_id": {
            "$oid":"5d85b311e180652980824193"
    },
    "date":{
            "$date":{ "$numberLong":"1569043209148" }
    },
    "title": "test",
    "image":"test image",
    "description":"test desc",
    "__v":{ 
           "$numberInt":"0"
    }
}

I am using MongoDB and my mapping looks like this:

    componentDidMount() {
        this.props.fetchSkills();
    }

    render() {

        const { skills } = this.props
        let skillData

        if (skills.length === 0) {

            return (
                <p>There are no skills to display</p>
            )

        } else {

            skillData = skills.map(skill => (

                <div key={skill._id}>       
                    <div>
                        <img src={skill.image} alt="" />
                    </div>

                    <div>
                        <h2>{skill.title}</h2>
                        <div>
                            <span>{skill.date}</span>
                        </div>
                        <div>
                            <p>{skill.description}</p>
                        </div>
                    </div>
                </div>

            ))
        }

        return (
            <div>

                {skillData}

            </div>
        )
    }

However, I get this error when I load the page:

TypeError: skills.map is not a function

  26 |            )
  27 |        } else {
  28 | 
> 29 |            skillData = skills.map(skill => (
  30 | ^               
  31 |                <div className="item" key={skill._id}>       
  32 |                

I think it's because .map can only iterate through arrays but I am trying to iterate through an object.

Answer 1

You need to have an array, to be able to iterate through it using the function .map()

So simply transform your object in an array of objects like this:

[
    {
        "_id": {
                "$oid":"5d85b311e180652980824193"
        },
        "date":{
                "$date":{ "$numberLong":"1569043209148" }
        },
        "title": "test",
        "image":"test image",
        "description":"test desc",
        "__v":{ 
               "$numberInt":"0"
        }
    }
]

And now you'll be able to successfully use .map()