Returning first object in array of objects (JavaScript)

Question

I'm having trouble with this function. I'm supposed to return the first element of an array, which I'm able to do with arrays of numbers or a string.

function firstElement(array) {
  if (array.length === 0) {
    return undefined;
  }
  if (array instanceof Array || typeof(array) === "string") {
    return array[0];
  }
}
firstElement([1, 2, 3]); // 1
firstElement([{ name: “Joseph” }, { name: “Ashley” }, { name: “Brandon” }]); // {name: “Joseph”}

However, when it comes to an array of objects, I'm not quite sure how I'm supposed to return the whole object ({name: "Joseph"}). At first, I tried doing it the same way I would return the first number in a number array, but I was thrown a SyntaxError. It seemed as simple as that but I'm just completely stuck now. I want it to be able to work for any {key: value} object and not just specifically names.

Can anyone see where I am wrong?

Looking at what the OP is doing with the type checking, the length check should not take place before the type check. Looking additionally at the possible return values, the implementation of firstElement could be much simplified based on the usage of Array.from and making sure that the passed argument is neither a null nor an undefined value ... function firstElement(value) { return Array.from(value != null ? value : [])[0]; } ... or in another variant something like ... const firstElement = value => Array.from(value ?? [])[0]; — Peter Seliger
– Peter Seliger, Commented Feb 25, 2021 at 11:18

DecPK · Accepted Answer · 2021-02-25 10:18:57Z

2

According to your object value, it should be string but you have used the wrong double quotes. It should be " " not “ ”.

You can also use single quote i.e ' '.Both are acceptable.

Everything else is working fine.

function firstElement(array) {
  if (array.length === 0) {
    return undefined;
  }
  if (array instanceof Array || typeof array === "string") {
    return array[0];
  }
}
const element1 = firstElement([1, 2, 3]); // 1
const element2 = firstElement([{ name: "Joseph" }, { name: "Ashley" }, { name: "Brandon" }]);

console.log( element1 );
console.log( element2 );

edited Feb 25, 2021 at 10:18

answered Feb 25, 2021 at 10:07

DecPK

25.4k6 gold badges32 silver badges46 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

napruto Over a year ago

Oh, wow. I didn't even realize that the quotes were different. Thank you!

Sandeep Chikhale · Accepted Answer · 2021-02-25 10:18:08Z

0

The object inside your array is incorrect, it should be a string that's why you are getting this issue. Just change “ to " in the object and your code will work as expected.

Try with the below array once.
[{ name : "Joseph" }, { name: "Ashley" }, { name: "Brandon" }]

function firstElement(array) {
      if (array.length === 0) {
        return undefined;
      }
      if (array instanceof Array || typeof array === "string") {
        return array[0];
      }
    }
   
    const first = firstElement([{ name: "Joseph" }, { name: "Ashley" }, { name: "Brandon" }]);
    console.log("first :", first);

edited Feb 25, 2021 at 10:18

answered Feb 25, 2021 at 10:09

Sandeep Chikhale

1,5162 gold badges21 silver badges36 bronze badges

Collectives™ on Stack Overflow

Returning first object in array of objects (JavaScript)

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related